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deepseek-harness/packages/core/tools/README.md
T
Tianyi Cui bd7fb31ae3 feat(tool-fs): editor-facing presentation for read/write/edit
The fs tools rendered as generic cards (title = tool name, raw file content) in
an ACP editor. Give them tool-owned presentation like bash/subagent have:

- read → title "Read <path>", kind read, offset/limit as rawInput
- write → title "Write <path>", kind edit
- edit → title "Edit <path>", kind edit, a clipped old→new rawInput summary

Add a provider-neutral `locations: { path, line? }[]` to ToolCallPresentation —
the files a call reads/modifies — so a capable editor can follow along / jump to
the file (read carries its offset as the line). The ACP bridge forwards it onto
the wire `tool_call` (ResolvedCallPresentation + call() + the tool_call build in
streamSessionEventUpdate). This flips the `locations` cell in the ACP feature
matrix to supported. The SDK already carries `tool_call.locations`
(ToolCallLocation `{ path, line? }`), so no ACP types leak into dsh-tools.

presentResult is intentionally omitted: it only receives `{ content, isError }`,
not the write/edit outcome, so titling by create-vs-overwrite or replacement
count would mean parsing the model-facing text — the static title stays.

Tests: pure presentCall assertions for all three tools incl. locations and the
edit rawInput clip; a bridge test drives the REAL fs tools through ToolPresenter
and asserts locations reaches the wire tool_call (proven to fail without the
forwarding line). New withFs harness option + dsh-fs devDeps on dsh-acp.
2026-07-02 19:36:17 +08:00

108 lines
8.1 KiB
Markdown

# dsh-tools
Tool registry and execution waterfall. Tool plugins register their schemas and executors; the agent loop executes calls through the `tools/execute` waterfall.
## Service: `ToolRegistry` (ctx key: `tools`)
### Public API
- `ctx.tools.register(definition: ToolDefinition): () => void` Register a tool. Disposed with the calling fiber.
- `ctx.tools.get(name: string): ToolDefinition | undefined`
- `ctx.tools.schemas(): ToolSchema[]` Schemas of all registered tools (without the `execute` functions). The shipped tools' schemas are catalogued in [docs/tool-catalog/tools.md](../../../docs/tool-catalog/tools.md), generated by booting each tool plugin and harvesting this method (see [the tool-schema-catalog RFC](../../../docs/rfc/implemented/process/2026-07-02-tool-schema-catalog.md)).
- `ctx.tools.execute(exec: ToolExecution): Promise<ToolExecutionResult>` Execute one tool call through the `tools/execute` waterfall.
### Injected services
`SystemPrompt` — the registry automatically feeds its tool schemas into the system-prompt assembly via `ctx.systemPrompt.tools()`.
### Events
| Event | Mode | Purpose |
|---|---|---|
| `tools/execute` | waterfall | Wrap/veto tool execution (sandbox, permission, hooks, plan mode) |
| `tools/change` | emit | A tool was registered or unregistered |
### Key types
- `ToolDefinition``ToolSchema` + `execute(args, exec): Promise<ContentBlock[]>`, plus optional `presentCall(args)` / `presentResult(args, result)` for tool-owned UI presentation (see below).
- `ToolExecution` — one pending tool call: `{ callId, name, arguments, agent?, signal? }`.
- `ToolExecutionResult` — outcome: `{ callId, content, isError, error? }`. On failure with a `HarnessError`, `error: { name, code }` carries the structured failure class alongside the model-facing text (the loop forwards it onto the `tool/result` session event for retry/sandbox plugins and replay).
- `ToolCallPresentation` / `ToolResultPresentation` — provider-neutral shapes a tool returns from `presentCall` / `presentResult` to own how a UI renders ITS calls (see "Tool-owned UI presentation").
### Extension points
- Tool plugins call `ctx.tools.register()` — schemas flow into the assembly automatically.
- The `tools/execute` waterfall is the single seam for sandbox, permission, hooks, and plan-mode plugins to wrap or veto a call. Listeners receive `(exec, next)`: call `next()` to proceed, or return a result without calling `next()` to short-circuit (veto).
- MCP servers: one plugin per server, discover tools, call `ctx.tools.register()` with the server's schemas.
### Typed tool parameter schemas
First-party plugin authors can use the `defineTool()` helper (exported from this package) for typed tool parameter schemas:
```ts
import { readFile } from 'node:fs/promises'
import type { Context } from 'cordis'
import { defineTool } from '@deepseek-ai/dsh-tools'
declare const ctx: Context
ctx.tools.register(defineTool({
name: 'read_file',
description: 'Read a file from disk.',
parameters: {
path: { type: 'string', required: true, description: 'Absolute file path' },
offset: { type: 'number' },
limit: { type: 'number' },
},
async execute(args, exec) {
// args is typed: { path: string; offset?: number; limit?: number }
const text = await readFile(args.path, 'utf8')
return [{ type: 'text', text }]
},
}))
```
The helper converts the author-facing `SchemaSpec` (with `required: true` as a per-property boolean) to standard JSON Schema for the wire format. Raw JSON-Schema tool definitions (from MCP servers) are still accepted by the registry directly.
A `defineTool` tool also **validates the model-generated arguments against its `SchemaSpec` before `execute` runs** (`validateArgs`). The model's JSON is untrusted — `InferArgs<S>` is a compile-time claim, not a runtime guarantee — so on a mismatch (missing required key, wrong primitive, bad enum member, nested violation) the tool throws a `ToolArgsError` (`code: 'INVALID_ARGS'`); the registry turns it into an `isError` result whose text lists the violations, which the model sees and self-corrects from. Validation mirrors the JSON Schema conversion exactly: extra keys are allowed, `default` is not applied, and an `object`/`array` prop without `properties`/`items` only type-checks. Raw-registered tools (MCP) are **not** validated by the harness — they validate their own input.
See `defineTool`, `validateArgs`, `ToolArgsError`, `SchemaSpec`, `InferArgs`, and `schemaSpecToJsonSchema` in the public API for details.
### Tool-owned UI presentation
A tool owns how ITS calls render in a UI (an editor's tool-call card, a CLI log line) — a UI plugin must NOT special-case tool names. A `ToolDefinition` may declare two optional, pure, display-only methods:
- `presentCall(args): ToolCallPresentation | undefined` — the PENDING state: a human-readable `title` (always-visible label), an optional `kind` (`read`/`edit`/`execute`/… for icon/treatment, default `other`), an optional `rawInput` (the salient input to show in a detail view — e.g. a shell command as a string, NOT the whole args object), an optional `content` (UI content shown alongside the title/card — e.g. a bash `description` as a text block above the terminal card), an optional `locations` (`{ path, line? }[]` — the files this call reads/modifies, so a capable UI can follow along / jump to them; the ACP bridge forwards them as `tool_call.locations`), and an optional `terminal` (a neutral `{ cwd? }` asking a capable UI to render this call as a TERMINAL, e.g. for `bash`).
- `presentResult(args, result): ToolResultPresentation | undefined` — the COMPLETED state, given the same `args` and the `{ content, isError }` result: an optional replacement `title`, reformatted `content` (e.g. wrap command output in a fenced ` ```console ` block — a UI-only affordance that must NOT appear in the model-facing `execute` result), and an optional `terminal` (the `{ output?, exitCode?, signal? }` for a terminal-rendered call). The `ToolTerminal` shape is provider-neutral; a UI bridge (the ACP bridge) maps it to a terminal card (with an exit-status pill) and a UI that can't ignores it and uses `content`.
Returning `undefined` (or omitting a method) tells a UI to fall back to a generic presentation (title = tool name, raw args as input, raw result content). Both methods must be **pure and side-effect-free**: a UI may call them during live streaming AND during a session-log replay, so they depend only on their arguments. With `defineTool`, `args` is the typed `InferArgs<S>` shape; the helper soft-validates before calling (a malformed/older logged arg shape yields `undefined` rather than throwing, since display must never crash a replay). The shapes are provider-neutral — the ACP bridge (`dsh-acp`) maps them to ACP `tool_call`/`tool_call_update` wire fields, and `dsh-tool-bash` is the reference implementation.
```ts
import { defineTool } from '@deepseek-ai/dsh-tools'
const bash = defineTool({
name: 'bash',
description: 'Run a shell command.',
parameters: {
command: { type: 'string', required: true, description: 'The command to run.' },
description: { type: 'string', required: true, description: 'One-line summary shown in the UI.' },
},
async execute(args) {
return [{ type: 'text', text: `ran: ${args.command}` }]
},
// The command is the readable title; the description rides as a content block.
presentCall: args => ({ title: args.command, kind: 'execute', rawInput: args.command, content: [{ type: 'text', text: args.description }] }),
// Wrap the output as a console block for the UI (not in the model-facing result).
presentResult: (_args, result) => {
const block = result.content.length === 1 ? result.content[0] : undefined
if (block === undefined || block.type !== 'text') return undefined
return { content: [{ type: 'text', text: '```console\n' + block.text + '\n```' }] }
},
})
```
### What is NOT here (TODO)
- **Tool shapes review** — when real tools land (e.g. a concurrency-safety hint for parallel execution); phase 1 executes tool calls sequentially.
- **Parallel execution** — the loop currently iterates tool calls sequentially.