feat(bash): generalize managed shell environment

packages/bash/tool-bash/README.md

@@ -22,11 +22,26 @@ The plugin also contributes the `tool:bash` prompt section (order 105) — the c
 
 `command`, `workdir`, and `timeoutMs` are resolved against the executor's config defaults via `ctx.bash.resolve()` before execution, so the executor seam (`BashExecSpec`) receives explicit `workdir`/`timeoutMs` values. The workdir default is applied in the tool layer (from the calling agent's `session.header.cwd`) BEFORE `resolve()` — the per-session cwd must come from `exec.agent`, since N sessions share one executor; only when no session cwd is available does the executor fall back to its own config / `process.cwd()`.
 
-### Session identity environment
+### Managed shell environment
 
-Every foreground and background call made for an agent receives `DSH_SESSION_ID=agent.session.header.id`. When the active persistence backend locates a JSONL artifact, the call also receives `DSH_SESSION_JSONL=<absolute target path>`; absent persistence and non-file backends still provide the id but omit the JSONL variable. The path is a location hint: lazy materialization means it may not exist on the first turn, and during an open turn it can omit buffered events that have not reached `session/flush`. Neither value is an authorization credential.
+Every foreground and background model bash call receives a newly collected trusted `DSH_*` environment. `DSH_HOME` is the absolute Harness home (`dshHome` config, then ambient `$DSH_HOME`, then `~/.dsh`) and `DSH_SHELL=1` identifies the managed child. Agent calls additionally receive `DSH_SESSION_ID=agent.session.header.id`; when the active persistence seam locates a JSONL artifact they also receive `DSH_SESSION_JSONL=<absolute target path>`. The JSONL path is a location hint: it may not exist before the first flush or contain the current buffered turn, and it is not an authorization credential.
 
-The overlay is computed from `ToolExecution.agent` for each call and passed through `BashExecRequest.env`; `process.env` is never modified, so concurrent parent/child agents keep separate values. The tool description names both variables so the model can inspect them without a permanent system-prompt section.
+`ctx.bashEnv` owns collection. Other plugins can register an effect-scoped contributor with a stable name, declared keys/descriptions, and `resolve(execution: ToolExecution)`; duplicate ownership and undeclared runtime keys fail loudly, while `list()` enumerates declarations without executing providers. Harness built-ins reserve `DSH_HOME`, `DSH_SHELL`, and `DSH_SESSION_ID`; tool-bash's persistence translator owns `DSH_SESSION_JSONL` by reading the backend-neutral `sessionPersistence.locate()` seam.
+
+```ts
+import type { Context } from 'cordis'
+import type {} from '@deepseek-ai/dsh-tool-bash'
+
+export function apply(ctx: Context): void {
+  ctx.bashEnv.register({
+    name: 'deployment-region',
+    variables: { DSH_DEPLOYMENT_REGION: { description: 'Current deployment region.' } },
+    resolve: execution => execution.agent === undefined ? {} : { DSH_DEPLOYMENT_REGION: 'cn-north' },
+  })
+}
+```
+
+The overlay is computed from the current `ToolExecution` and passed through the dedicated `BashExecRequest.dshEnv` channel. The local executor removes all inherited `DSH_*` before merging that snapshot, so nested harnesses and concurrent parent/child agents cannot leak stale identities. `process.env` is never modified. The tool description teaches the generic `$DSH_*` convention rather than naming persistence-specific variables or adding a permanent system-prompt section.
 
 Result text: stdout, then a `[stderr]` section, then status markers — `[sandbox: file access denied under <mode> mode]` when a sandboxing executor classified the failure as a policy denial (reported first so `[exit code: N]` stays the last line; the static description tells the model a denial is policy, not a command bug, and forbids retrying around it), `[timed out after Nms]` whenever the executor's timer fired (reported independently of how the process ended, so a command that traps SIGTERM and exits 0 still shows it), `[killed by signal: …]` for a signal death, `[exit code: N]` for a non-zero exit (reported, **not** `isError`: the model decides how to react), and `[output truncated; full output: <path>]` when the tail was kept and a safe spill file is available. If the executor knows output was dropped but cannot safely advertise a complete spill file, the path is reported as `(unavailable)`. Only infrastructure failures (spawn errors, aborts) surface as `isError` results.
 
@@ -52,7 +67,7 @@ When a background task finishes, a short notice is injected into the owning agen
 
 ## The tool builds its request from named args only
 
-The `BashExecRequest` seam carries optional `stdin` and `env`, used by trusted consumers. This tool does **not** expose them as model parameters: it builds the request from named schema fields and adds only the session overlay above, so model-supplied `env`/`stdin` keys are ignored and cannot replace the trusted values. This is not a trust boundary — a model already has equivalent power through shell syntax (`FOO=bar cmd`, a heredoc), and the real defense against leaking ambient secrets is `dsh-bash-local`'s credential scrub. Regression guards assert extra model fields never enter the request while the trusted overlay still does. See [the bash-stdin-env RFC](../../../docs/rfc/implemented/architecture/2026-06-30-bash-stdin-env-trusted-plugin-surface.md).
+The `BashExecRequest` seam carries optional `stdin` and ordinary `env` for in-process consumers plus the harness-owned `dshEnv` channel above. This tool does **not** expose any of them as model parameters: it builds the request from named schema fields, so model-supplied `env`/`stdin` keys are ignored and cannot replace the managed values. A model already has equivalent command-local power through shell syntax (`FOO=bar cmd`, a heredoc); ambient-secret protection comes from `dsh-bash-local`'s credential scrub, while `dshEnv` ownership prevents stale or spoofed Harness context. See [the bash-stdin-env RFC](../../../docs/rfc/implemented/architecture/2026-06-30-bash-stdin-env-trusted-plugin-surface.md).
 
 ## Permissions and escalation
 

packages/bash/tool-bash/package.json

@@ -32,6 +32,9 @@
     "@deepseek-ai/dsh-tools": "^0.0.1",
     "cordis": "^4.0.0-rc.6"
   },
+  "dependencies": {
+    "schemastery": "^3.18.0"
+  },
   "devDependencies": {
     "@deepseek-ai/dsh-agent": "workspace:^",
     "@deepseek-ai/dsh-agent-loop": "workspace:^",

packages/bash/tool-bash/src/index.ts

@@ -55,8 +55,10 @@
  * @module @deepseek-ai/dsh-tool-bash
  */
 
-import type { Context } from 'cordis'
-import { isAbsolute, resolve as resolvePath } from 'node:path'
+import { Service, type Context } from 'cordis'
+import z from 'schemastery'
+import { homedir } from 'node:os'
+import { isAbsolute, join, resolve as resolvePath } from 'node:path'
 import { defineTool } from '@deepseek-ai/dsh-tools'
 import type { GenericCallView, TerminalCallView, ToolExecution, ToolResult, ToolResultView } from '@deepseek-ai/dsh-tools'
 import type { Agent } from '@deepseek-ai/dsh-agent'
@@ -69,11 +71,178 @@ import type {} from '@deepseek-ai/dsh-system-prompt'
 import type {} from '@deepseek-ai/dsh-user-approval'
 import type { SandboxMode } from '@deepseek-ai/dsh-sandbox'
 import { BashTaskId, OwnerToken, effectiveSandboxMode } from '@deepseek-ai/dsh-bash'
-import type { BashRunResult, BashTask, CollectedOutput } from '@deepseek-ai/dsh-bash'
+import type { BashRunResult, BashTask, CollectedOutput, DshEnvironment } from '@deepseek-ai/dsh-bash'
+
+declare module 'cordis' {
+  interface Context {
+    bashEnv: BashEnvRegistry
+  }
+}
 
 export const name = 'tool-bash'
 export const inject = ['tools', 'bash', 'systemPrompt']
 
+/** Configuration for the bash tool and its managed child environment. */
+export interface Config {
+  /** DeepSeek Harness home directory exposed as `DSH_HOME`; defaults to `$DSH_HOME` or `~/.dsh`. */
+  dshHome?: string
+}
+
+/** Runtime configuration schema for the bash tool plugin. */
+export const Config: z<Config> = z.object({
+  dshHome: z.string(),
+})
+
+/** Model-visible metadata for one managed `DSH_*` environment variable. */
+export interface BashEnvVariable {
+  /** Concise description of the environment fact represented by the variable. */
+  description: string
+}
+
+/**
+ * A plugin contribution to the managed environment of each model bash call.
+ * Declared keys make ownership conflicts detectable before the first command;
+ * `resolve` computes only the values available for the current execution.
+ */
+export interface BashEnvContributor {
+  /** Stable contributor name used in diagnostics and duplicate detection. */
+  name: string
+  /** Complete set of `DSH_*` keys this contributor may return. */
+  variables: Readonly<Record<`DSH_${string}`, BashEnvVariable>>
+  /**
+   * Resolve this contributor's available values for one tool execution.
+   * @param execution - the bash tool execution and its optional calling agent.
+   * @returns a partial map containing only keys declared in {@link variables}.
+   */
+  resolve(execution: ToolExecution): Readonly<Partial<Record<`DSH_${string}`, string>>>
+}
+
+/** An enumerable declaration returned by {@link BashEnvRegistry.list}. */
+export interface BashEnvVariableInfo extends BashEnvVariable {
+  /** Contributor that owns the variable. */
+  contributor: string
+  /** Declared `DSH_*` environment variable name. */
+  key: `DSH_${string}`
+}
+
+const RESERVED_BASH_ENV_KEYS = new Set<`DSH_${string}`>([
+  'DSH_HOME',
+  'DSH_SHELL',
+  'DSH_SESSION_ID',
+])
+const BASH_ENV_KEY = /^DSH_[A-Z][A-Z0-9_]*$/
+
+/**
+ * Registry (`ctx.bashEnv`) for trusted, per-execution `DSH_*` variables.
+ * The namespace is rebuilt for every model bash call: ambient `DSH_*` values
+ * are discarded by the executor, then the registry's current snapshot is
+ * injected. Built-in shell facts remain owned by the registry itself while
+ * plugins can register additional, enumerable facts with effect-scoped
+ * disposal.
+ */
+export class BashEnvRegistry extends Service {
+  private readonly contributors = new Map<string, BashEnvContributor>()
+  private readonly keyOwners = new Map<`DSH_${string}`, string>()
+  private readonly dshHome: string
+
+  /**
+   * Create and install the `ctx.bashEnv` service.
+   * @param ctx - Cordis context that owns the service and registrations.
+   * @param config - home-directory configuration for the built-in variables.
+   */
+  constructor(ctx: Context, config: Config = {}) {
+    super(ctx, 'bashEnv')
+    this.dshHome = resolvePath(config.dshHome ?? process.env.DSH_HOME ?? join(homedir(), '.dsh'))
+  }
+
+  /**
+   * Register one environment contributor. Names and keys are unique; built-in
+   * keys are reserved. Registration is disposed with the calling plugin fiber.
+   * @param contributor - declared key ownership and per-execution resolver.
+   * @returns the disposer that unregisters the contribution.
+   */
+  register(contributor: BashEnvContributor): () => void {
+    const dispose = this.ctx.effect(function* (this: BashEnvRegistry) {
+      if (contributor.name.trim().length === 0) {
+        throw new Error('bash env contributor name must be non-empty')
+      }
+      if (this.contributors.has(contributor.name)) {
+        throw new Error(`bash env contributor "${contributor.name}" is already registered`)
+      }
+
+      const variables = Object.entries(contributor.variables) as [`DSH_${string}`, BashEnvVariable][]
+      for (const [key, variable] of variables) {
+        if (!BASH_ENV_KEY.test(key)) {
+          throw new Error(`bash env contributor "${contributor.name}" declared invalid key "${key}"`)
+        }
+        if (RESERVED_BASH_ENV_KEYS.has(key)) {
+          throw new Error(`bash env contributor "${contributor.name}" cannot own reserved key "${key}"`)
+        }
+        if (variable.description.trim().length === 0) {
+          throw new Error(`bash env contributor "${contributor.name}" must describe "${key}"`)
+        }
+        const owner = this.keyOwners.get(key)
+        if (owner !== undefined) {
+          throw new Error(`bash env key "${key}" is already owned by contributor "${owner}"; contributor "${contributor.name}" cannot also own it`)
+        }
+      }
+
+      this.contributors.set(contributor.name, contributor)
+      for (const [key] of variables) this.keyOwners.set(key, contributor.name)
+      yield () => {
+        this.contributors.delete(contributor.name)
+        for (const [key] of variables) this.keyOwners.delete(key)
+      }
+    }.bind(this), 'bashEnv.register()')
+    return () => void dispose()
+  }
+
+  /**
+   * Build the trusted `DSH_*` snapshot for one bash tool execution.
+   * @param execution - the current tool execution.
+   * @returns an immutable environment overlay containing built-ins and current contributions.
+   */
+  collect(execution: ToolExecution): DshEnvironment {
+    const values: Record<`DSH_${string}`, string> = {
+      DSH_HOME: this.dshHome,
+      DSH_SHELL: '1',
+    }
+    if (execution.agent !== undefined) {
+      values.DSH_SESSION_ID = execution.agent.session.header.id
+    }
+
+    for (const contributor of [...this.contributors.values()].sort((left, right) => left.name.localeCompare(right.name))) {
+      const resolved = contributor.resolve(execution)
+      for (const [rawKey, value] of Object.entries(resolved)) {
+        const key = rawKey as `DSH_${string}`
+        if (!Object.hasOwn(contributor.variables, key)) {
+          throw new Error(`bash env contributor "${contributor.name}" returned undeclared key "${key}"`)
+        }
+        if (typeof value !== 'string') {
+          throw new Error(`bash env contributor "${contributor.name}" returned a non-string value for "${key}"`)
+        }
+        values[key] = value
+      }
+    }
+
+    return Object.freeze(Object.fromEntries(Object.entries(values).sort(([left], [right]) => left.localeCompare(right))))
+  }
+
+  /**
+   * Enumerate plugin-contributed variables without executing their resolvers.
+   * @returns declarations sorted by environment variable name.
+   */
+  list(): BashEnvVariableInfo[] {
+    return [...this.contributors.values()]
+      .flatMap(contributor => Object.entries(contributor.variables).map(([key, variable]) => ({
+        contributor: contributor.name,
+        description: variable.description,
+        key: key as `DSH_${string}`,
+      })))
+      .sort((left, right) => left.key.localeCompare(right.key))
+  }
+}
+
 /**
  * Validate the constraints the SchemaSpec can't express. `defineTool` now
  * validates parsed args against the SchemaSpec before `execute` runs (the
@@ -168,8 +337,7 @@ function bashDescription(escalationModes: readonly SandboxMode[]): string {
   const base = 'Execute a bash command (`bash -c`) and return its stdout/stderr. '
     + 'Each call runs in a fresh shell: no state (cwd, variables, functions) persists between calls — '
     + 'pass `workdir` instead of using `cd`. Non-zero exits are reported as `[exit code: N]`. '
-    + 'The current agent session id is available as `$DSH_SESSION_ID`; when JSONL persistence is configured, '
-    + '`$DSH_SESSION_JSONL` is its absolute target path and may not exist or contain the current unflushed turn yet. '
+    + 'Current harness environment facts are exposed through managed `$DSH_*` variables; inspect them when needed. '
     + 'Commands may run under a file sandbox; a blocked file operation is reported as `[sandbox: file access denied under <mode> mode]` — a policy denial, not a bug in the command; do not retry another way (a background task reports the same marker via bash_output once it has finished). '
     + 'Long output is truncated to its tail; the full output is saved to a file whose path is reported when available. '
     + 'Set `run_in_background: true` for long-running commands: the call returns a task id immediately; '
@@ -397,22 +565,6 @@ function resolveWorkdir(modelWorkdir: string | undefined, exec: { agent?: Agent
   return modelWorkdir
 }
 
-/**
- * Build the trusted per-execution session environment. Identity always comes
- * from the calling agent's immutable session header; an optional JSONL path
- * comes from the active persistence backend's side-effect-free locator. A
- * non-agent caller has no current session, so it receives neither variable.
- */
-function sessionEnvironment(ctx: Context, exec: { agent?: Agent }): Record<string, string> | undefined {
-  const agent = exec.agent
-  if (agent === undefined) return undefined
-
-  const env: Record<string, string> = { DSH_SESSION_ID: agent.session.header.id }
-  const location = ctx.get('sessionPersistence')?.locate(agent.session.header)
-  if (location?.kind === 'jsonl') env.DSH_SESSION_JSONL = location.path
-  return env
-}
-
 /** Status line for background task reads. */
 function statusLine(task: BashTask): string {
   switch (task.status) {
@@ -422,7 +574,23 @@ function statusLine(task: BashTask): string {
   }
 }
 
-export function apply(ctx: Context): void {
+export function apply(ctx: Context, config: Config = {}): void {
+  const bashEnv = new BashEnvRegistry(ctx, config)
+  bashEnv.register({
+    name: 'session-persistence',
+    variables: {
+      DSH_SESSION_JSONL: {
+        description: 'Absolute target path of the current session JSONL when the active persistence backend provides one.',
+      },
+    },
+    resolve(execution) {
+      const agent = execution.agent
+      if (agent === undefined) return {}
+      const location = ctx.get('sessionPersistence')?.locate(agent.session.header)
+      return location?.kind === 'jsonl' ? { DSH_SESSION_JSONL: location.path } : {}
+    },
+  })
+
   // The bash tools' cross-call HABIT, which the per-tool descriptions cannot
   // carry (they describe one call each): the exit-code marker is only useful
   // if the model actually checks it every time.
@@ -614,13 +782,13 @@ export function apply(ctx: Context): void {
       // session runs in its own workspace (see resolveWorkdir); an explicit
       // model workdir still wins.
       const workdir = resolveWorkdir(args.workdir, exec)
-      const env = sessionEnvironment(ctx, exec)
+      const dshEnv = bashEnv.collect(exec)
       const request = {
         command: args.command,
         ...workdir !== undefined ? { workdir } : {},
         ...args.timeoutMs !== undefined ? { timeoutMs: args.timeoutMs } : {},
         ...exec.signal ? { signal: exec.signal } : {},
-        ...env !== undefined ? { env } : {},
+        dshEnv,
         ...sandboxMode !== undefined ? { sandboxMode } : {},
       }
       if (args.run_in_background === true) {

packages/bash/tool-bash/tests/bash-env.spec.ts

@@ -0,0 +1,189 @@
+import { homedir } from 'node:os'
+import { join, resolve } from 'node:path'
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import { Context } from 'cordis'
+import { CallId } from '@deepseek-ai/dsh-llm'
+import type { Agent } from '@deepseek-ai/dsh-agent'
+import type { ToolExecution } from '@deepseek-ai/dsh-tools'
+import { BashEnvRegistry } from '@deepseek-ai/dsh-tool-bash'
+
+afterEach(() => vi.unstubAllEnvs())
+
+function execution(sessionId?: string): ToolExecution {
+  return {
+    callId: CallId('bash-env-call'),
+    name: 'bash',
+    arguments: { command: 'true' },
+    ...(sessionId === undefined
+      ? {}
+      : { agent: { session: { header: { version: 0, id: sessionId, createdAt: 0 } } } as Agent }),
+  }
+}
+
+describe('BashEnvRegistry', () => {
+  it('collects unconditional shell facts and the current agent session id', () => {
+    const ctx = new Context()
+    const registry = new BashEnvRegistry(ctx, { dshHome: './test-dsh-home' })
+
+    expect(registry.collect(execution())).toEqual({
+      DSH_HOME: resolve('./test-dsh-home'),
+      DSH_SHELL: '1',
+    })
+    expect(registry.collect(execution('session-a'))).toEqual({
+      DSH_HOME: resolve('./test-dsh-home'),
+      DSH_SESSION_ID: 'session-a',
+      DSH_SHELL: '1',
+    })
+  })
+
+  it('resolves DSH_HOME from the ambient override or the user-home default', () => {
+    vi.stubEnv('DSH_HOME', './ambient-dsh-home')
+    const fromEnvironment = new BashEnvRegistry(new Context())
+    expect(fromEnvironment.collect(execution()).DSH_HOME).toBe(resolve('./ambient-dsh-home'))
+
+    vi.stubEnv('DSH_HOME', undefined)
+    const fromDefault = new BashEnvRegistry(new Context())
+    expect(fromDefault.collect(execution()).DSH_HOME).toBe(join(homedir(), '.dsh'))
+  })
+
+  it('collects declared contributor variables and omits unavailable values', () => {
+    const ctx = new Context()
+    const registry = new BashEnvRegistry(ctx, { dshHome: './test-dsh-home' })
+    registry.register({
+      name: 'optional-session-fact',
+      variables: {
+        DSH_SESSION_OPTIONAL: { description: 'Optional session-scoped test fact.' },
+      },
+      resolve: exec => exec.agent === undefined ? {} : { DSH_SESSION_OPTIONAL: exec.agent.session.header.id },
+    })
+    registry.register({
+      name: 'always-available-fact',
+      variables: {
+        DSH_ALWAYS_AVAILABLE: { description: 'Always-available test fact.' },
+      },
+      resolve: () => ({ DSH_ALWAYS_AVAILABLE: 'yes' }),
+    })
+
+    expect(registry.collect(execution())).not.toHaveProperty('DSH_SESSION_OPTIONAL')
+    expect(registry.collect(execution()).DSH_ALWAYS_AVAILABLE).toBe('yes')
+    expect(registry.collect(execution('session-b')).DSH_SESSION_OPTIONAL).toBe('session-b')
+    expect(registry.list()).toEqual([
+      {
+        contributor: 'always-available-fact',
+        description: 'Always-available test fact.',
+        key: 'DSH_ALWAYS_AVAILABLE',
+      },
+      {
+        contributor: 'optional-session-fact',
+        description: 'Optional session-scoped test fact.',
+        key: 'DSH_SESSION_OPTIONAL',
+      },
+    ])
+  })
+
+  it('rejects duplicate variable ownership at registration time', () => {
+    const ctx = new Context()
+    const registry = new BashEnvRegistry(ctx, { dshHome: './test-dsh-home' })
+    registry.register({
+      name: 'first',
+      variables: { DSH_SHARED: { description: 'First owner.' } },
+      resolve: () => ({ DSH_SHARED: 'first' }),
+    })
+
+    expect(() => registry.register({
+      name: 'second',
+      variables: { DSH_SHARED: { description: 'Second owner.' } },
+      resolve: () => ({ DSH_SHARED: 'second' }),
+    })).toThrow(/DSH_SHARED.*first.*second|DSH_SHARED.*second.*first/)
+  })
+
+  it('rejects duplicate contributor names and malformed declarations', () => {
+    const registry = new BashEnvRegistry(new Context(), { dshHome: './test-dsh-home' })
+    registry.register({
+      name: 'declared',
+      variables: { DSH_DECLARED: { description: 'Declared fact.' } },
+      resolve: () => ({}),
+    })
+
+    expect(() => registry.register({
+      name: 'declared',
+      variables: { DSH_ANOTHER: { description: 'Another fact.' } },
+      resolve: () => ({}),
+    })).toThrow(/already registered/)
+    expect(() => registry.register({
+      name: ' ',
+      variables: { DSH_BLANK_NAME: { description: 'Blank owner.' } },
+      resolve: () => ({}),
+    })).toThrow(/name must be non-empty/)
+    expect(() => registry.register({
+      name: 'invalid-key',
+      variables: { dsh_invalid: { description: 'Invalid key.' } } as unknown as Record<'DSH_INVALID', { description: string }>,
+      resolve: () => ({}),
+    })).toThrow(/invalid key/)
+    expect(() => registry.register({
+      name: 'reserved-key',
+      variables: { DSH_HOME: { description: 'Reserved key.' } },
+      resolve: () => ({}),
+    })).toThrow(/reserved key/)
+    expect(() => registry.register({
+      name: 'blank-description',
+      variables: { DSH_BLANK_DESCRIPTION: { description: ' ' } },
+      resolve: () => ({}),
+    })).toThrow(/must describe/)
+  })
+
+  it('rejects undeclared variables returned by a contributor', () => {
+    const ctx = new Context()
+    const registry = new BashEnvRegistry(ctx, { dshHome: './test-dsh-home' })
+    registry.register({
+      name: 'drifted-provider',
+      variables: { DSH_DECLARED: { description: 'Declared fact.' } },
+      resolve: () => ({ DSH_UNDECLARED: 'bad' }),
+    })
+
+    expect(() => registry.collect(execution())).toThrow(/drifted-provider.*DSH_UNDECLARED/)
+  })
+
+  it('rejects non-string values returned by a contributor', () => {
+    const registry = new BashEnvRegistry(new Context(), { dshHome: './test-dsh-home' })
+    registry.register({
+      name: 'wrong-value-type',
+      variables: { DSH_STRING: { description: 'String fact.' } },
+      resolve: () => ({ DSH_STRING: 42 }) as unknown as Record<'DSH_STRING', string>,
+    })
+
+    expect(() => registry.collect(execution())).toThrow(/wrong-value-type.*non-string.*DSH_STRING/)
+  })
+
+  it('removes an effect-scoped contributor when its plugin is disposed', async () => {
+    const ctx = new Context()
+    const registry = new BashEnvRegistry(ctx, { dshHome: './test-dsh-home' })
+    const fiber = await ctx.plugin({
+      inject: ['bashEnv'],
+      apply(inner: Context) {
+        inner.bashEnv.register({
+          name: 'temporary',
+          variables: { DSH_TEMPORARY: { description: 'Temporary fact.' } },
+          resolve: () => ({ DSH_TEMPORARY: 'present' }),
+        })
+      },
+    })
+
+    expect(registry.collect(execution()).DSH_TEMPORARY).toBe('present')
+    await fiber.dispose()
+    expect(registry.collect(execution())).not.toHaveProperty('DSH_TEMPORARY')
+  })
+
+  it('returns an explicit contributor disposer', () => {
+    const registry = new BashEnvRegistry(new Context(), { dshHome: './test-dsh-home' })
+    const dispose = registry.register({
+      name: 'explicit-disposal',
+      variables: { DSH_EXPLICIT_DISPOSAL: { description: 'Explicitly disposed fact.' } },
+      resolve: () => ({ DSH_EXPLICIT_DISPOSAL: 'present' }),
+    })
+
+    expect(registry.collect(execution()).DSH_EXPLICIT_DISPOSAL).toBe('present')
+    dispose()
+    expect(registry.collect(execution())).not.toHaveProperty('DSH_EXPLICIT_DISPOSAL')
+  })
+})

packages/bash/tool-bash/tests/integration.spec.ts

@@ -1,4 +1,4 @@
-import { afterEach, describe, expect, it } from 'vitest'
+import { afterEach, describe, expect, it, vi } from 'vitest'
 import { Context } from 'cordis'
 import { existsSync, mkdtempSync, readFileSync, rmSync } from 'node:fs'
 import { tmpdir } from 'node:os'
@@ -21,7 +21,7 @@ import { MockAdapter, textResponse, toolCallResponse } from '../../../core/agent
  * through the agent loop, exercising the same seams a live model would
  * (tool/call + tool/result session events, agent.inject notifications).
  */
-async function harness(adapter: MockAdapter, sessionRoot?: string) {
+async function harness(adapter: MockAdapter, sessionRoot?: string, dshHome?: string) {
   const ctx = new Context()
   await ctx.plugin(LlmService)
   await ctx.plugin(SessionStore)
@@ -31,13 +31,16 @@ async function harness(adapter: MockAdapter, sessionRoot?: string) {
   await ctx.plugin(AgentRegistry)
   await ctx.plugin(AgentLoop, { agents: [] })
   await ctx.plugin(LocalBashExecutor, { timeoutMs: 10_000 })
-  await ctx.plugin(ToolBash)
+  await ctx.plugin(ToolBash, dshHome === undefined ? {} : { dshHome })
   ctx.llm.registerAdapter(['mock'], adapter)
   return ctx
 }
 
 const dirs: string[] = []
-afterEach(() => { for (const dir of dirs.splice(0)) rmSync(dir, { recursive: true, force: true }) })
+afterEach(() => {
+  vi.unstubAllEnvs()
+  for (const dir of dirs.splice(0)) rmSync(dir, { recursive: true, force: true })
+})
 
 function waitForIdle(ctx: Context, agent: ReactLoopAgent): Promise<void> {
   return new Promise((resolve) => {
@@ -79,14 +82,16 @@ describe('bash tool through the agent loop', () => {
   it('first-turn bash receives session identity before the lazy JSONL file materializes', async () => {
     const root = mkdtempSync(join(tmpdir(), 'dsh-bash-session-env-'))
     dirs.push(root)
+    const dshHome = join(root, 'dsh-home')
+    vi.stubEnv('DSH_STALE_PARENT', 'stale')
     const adapter = new MockAdapter([
       toolCallResponse('call-1', 'bash', {
-        command: 'printf \'%s\\n%s\\n\' "$DSH_SESSION_ID" "$DSH_SESSION_JSONL"; if [ -e "$DSH_SESSION_JSONL" ]; then printf \'present\\n\'; else printf \'absent\\n\'; fi',
+        command: 'printf \'%s\\n%s\\n%s\\n%s\\n%s\\n\' "$DSH_HOME" "$DSH_SHELL" "$DSH_SESSION_ID" "$DSH_SESSION_JSONL" "${DSH_STALE_PARENT-unset}"; if [ -e "$DSH_SESSION_JSONL" ]; then printf \'present\\n\'; else printf \'absent\\n\'; fi',
         description: 'inspect session environment',
       }),
       textResponse('Session environment inspected.'),
     ])
-    const ctx = await harness(adapter, root)
+    const ctx = await harness(adapter, root, dshHome)
     const handle = ctx.agents.create({
       agentId: AgentId('session-env'),
       sessionId: SessionId('session-env-id'),
@@ -100,7 +105,7 @@ describe('bash tool through the agent loop', () => {
     await waitForIdle(ctx, agent)
 
     const result = findEvent(events(agent), 'tool/result')
-    expect(resultText(result)).toBe(`session-env-id\n${location?.path}\nabsent\n`)
+    expect(resultText(result)).toBe(`${dshHome}\n1\nsession-env-id\n${location?.path}\nunset\nabsent\n`)
     expect(existsSync(location!.path)).toBe(true)
     const header = JSON.parse(readFileSync(location!.path, 'utf8').split('\n')[0]!) as { type: string; id: string }
     expect(header).toMatchObject({ type: 'session', id: 'session-env-id' })

packages/bash/tool-bash/tests/tools.spec.ts

@@ -892,6 +892,8 @@ describe('tool-owned UI presentation (presentCall / presentResult)', () => {
 })
 
 describe('the model-facing bash tool builds its request from named args only (no {...args} forward)', () => {
+  const recordingDshHome = join(spillDir, 'dsh-home')
+
   /**
    * Records every {@link BashExecRequest} the consumer hands to `resolve()`, so a
    * test can assert what the model-facing tool DID and DID NOT forward. The `bash`
@@ -899,7 +901,7 @@ describe('the model-facing bash tool builds its request from named args only (no
    * model that power), so it must build its request from named args only and
    * never spread unknown tool-call keys into it. This guard's job is to catch a
    * future refactor that blindly forwards `...args` — which would silently thread
-   * model input into the post-scrub `env` merge — NOT to defend a trust boundary
+   * model input into the ordinary `env` channel — NOT to defend a trust boundary
    * (the credential scrub in dsh-bash-local is the security control; see the
    * bash-stdin-env RFC). Foreground `run()` returns a canned result; `start()` is
    * unused here.
@@ -915,6 +917,7 @@ describe('the model-facing bash tool builds its request from named args only (no
         ...request.signal ? { signal: request.signal } : {},
         ...request.stdin !== undefined ? { stdin: request.stdin } : {},
         ...request.env !== undefined ? { env: request.env } : {},
+        ...request.dshEnv !== undefined ? { dshEnv: request.dshEnv } : {},
         owner: request.owner,
         sandboxMode: request.sandboxMode,
       }
@@ -943,15 +946,15 @@ describe('the model-facing bash tool builds its request from named args only (no
       await ctx.plugin(SessionPersistenceJsonl, { root: join(spillDir, 'jsonl') })
     }
     await ctx.plugin(RecordingBashExecutor)
-    await ctx.plugin(ToolBash)
+    await ctx.plugin(ToolBash, { dshHome: recordingDshHome })
     return { ctx, bash: ctx.bash as RecordingBashExecutor }
   }
 
-  it('describes the trusted session variables to the model', async () => {
+  it('describes the managed harness environment namespace to the model', async () => {
     const { ctx } = await setupRecording()
     const description = ctx.tools.get('bash')?.description ?? ''
-    expect(description).toContain('DSH_SESSION_ID')
-    expect(description).toContain('DSH_SESSION_JSONL')
+    expect(description).toContain('$DSH_*')
+    expect(description).not.toContain('DSH_SESSION_JSONL')
   })
 
   it('injects the session id and JSONL target path into a foreground request', async () => {
@@ -966,9 +969,11 @@ describe('the model-facing bash tool builds its request from named args only (no
       agent,
     })
 
-    expect(bash.requests[0]?.env).toEqual({
+    expect(bash.requests[0]?.dshEnv).toEqual({
+      DSH_HOME: recordingDshHome,
       DSH_SESSION_ID: 'request-fg',
       DSH_SESSION_JSONL: path,
+      DSH_SHELL: '1',
     })
   })
 
@@ -989,13 +994,16 @@ describe('the model-facing bash tool builds its request from named args only (no
       agent,
     })
 
-    expect(bash.requests[0]?.env).toEqual({
+    expect(bash.requests[0]?.env).toBeUndefined()
+    expect(bash.requests[0]?.dshEnv).toEqual({
+      DSH_HOME: recordingDshHome,
       DSH_SESSION_ID: 'request-bg',
       DSH_SESSION_JSONL: path,
+      DSH_SHELL: '1',
     })
   })
 
-  it('injects only the stable session id when no JSONL locator is available', async () => {
+  it('injects built-ins and the stable session id when no JSONL locator is available', async () => {
     const { ctx, bash } = await setupRecording()
     const agent = registerFakeAgent(ctx, 'request-id-only', () => undefined)
     const ambient = process.env.DSH_SESSION_ID
@@ -1007,7 +1015,11 @@ describe('the model-facing bash tool builds its request from named args only (no
       agent,
     })
 
-    expect(bash.requests[0]?.env).toEqual({ DSH_SESSION_ID: 'request-id-only' })
+    expect(bash.requests[0]?.dshEnv).toEqual({
+      DSH_HOME: recordingDshHome,
+      DSH_SESSION_ID: 'request-id-only',
+      DSH_SHELL: '1',
+    })
     expect(process.env.DSH_SESSION_ID).toBe(ambient)
   })
 
@@ -1025,17 +1037,21 @@ describe('the model-facing bash tool builds its request from named args only (no
       })
     }
 
-    expect(bash.requests.map(request => request.env)).toEqual([
+    expect(bash.requests.map(request => request.dshEnv)).toEqual([
       {
+        DSH_HOME: recordingDshHome,
         DSH_SESSION_ID: 'request-parent',
         DSH_SESSION_JSONL: ctx.sessionPersistence.locate(parent.session.header)?.path,
+        DSH_SHELL: '1',
       },
       {
+        DSH_HOME: recordingDshHome,
         DSH_SESSION_ID: 'request-child',
         DSH_SESSION_JSONL: ctx.sessionPersistence.locate(child.session.header)?.path,
+        DSH_SHELL: '1',
       },
     ])
-    expect(bash.requests[0]?.env?.DSH_SESSION_JSONL).not.toBe(bash.requests[1]?.env?.DSH_SESSION_JSONL)
+    expect(bash.requests[0]?.dshEnv?.DSH_SESSION_JSONL).not.toBe(bash.requests[1]?.dshEnv?.DSH_SESSION_JSONL)
   })
 
   it('does not forward env/stdin even when the model includes them as extra arguments', async () => {