Rebuild of the region machinery (PR3) on the post-#904 Typert projection: renderPageRegion/renderInheritedPage live in dsh-typert-generator beside the projection; scripts/gen-cordis-catalog.ts owns the curated SERVICE_PAGE / EVENT_SCOPE_PAGE / SERVICE_WALK_EXEMPTIONS / LINK_MAP partition (fail-loud in both directions, with the independent Context-merge scan backstopping the projection's blind spot), spliceRegion, and the guarded pair auto-record. docs/cordis-catalog/ is deleted: the flat events/services catalogs dissolve into per-page regions and docs/cordis-catalog/core moves to docs/cordis-api/ with the inherited tier as its own generated page. The partition absorbs the post-regrouping surface: ctx.typert → invariants.md, ctx.directoryPicker → workspace.md, skills/* events → skills.md, and the four launcher-provided tui accessor values join the named exemptions.
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Services and dependencies
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A service is a capability one plugin exposes to other plugins. inject declares the services a plugin requires.
What is a service?
In Harness, tools, llm, and agents are services. Each is a named capability mounted on ctx:
ctx.tools // ToolRegistry service
ctx.llm // LLM service
ctx.agents // Agent service
Any plugin can provide a service for other plugins to consume.
Consume a service
Declare inject to use an existing service:
export const inject = ['tools']
export function apply(ctx: Context) {
// ctx.tools exists and is ready here.
ctx.tools.register(/* ... */)
}
When apply runs, every service declared by inject is ready. If a service is not ready, the plugin waits instead of running.
Provide a service
Extend Service
import { Service, type Context } from 'cordis'
export default class MetricsService extends Service {
static inject = ['llm'] // A service may depend on other services.
constructor(ctx: Context) {
super(ctx, 'metrics') // 'metrics' is the service name.
}
// Public service method.
record(event: string, value: number) {
// ...
}
}
After loading this plugin, consumers access the service as ctx.metrics:
export const inject = ['metrics']
export function apply(ctx: Context) {
ctx.metrics.record('tool_call', 1)
}
Declare its type
Use TypeScript declaration merging to type ctx.metrics:
import { Service, type Context } from 'cordis'
declare module 'cordis' {
interface Context {
metrics: MetricsService
}
}
export default class MetricsService extends Service {
constructor(ctx: Context) {
super(ctx, 'metrics')
}
record(event: string, value: number) { /* ... */ }
}
Dependency behavior
Required and optional dependencies
// Required: the plugin does not load while the service is absent.
export const inject = ['tools']
// Optional: omit inject and query with ctx.get() at the use site.
export function apply(ctx: Context) {
const metrics = ctx.get('metrics')
metrics?.record('plugin_loaded', 1)
}
When a service disappears
If a required service disappears while the application is running, for example because its provider unloads:
- Dependent plugins dispose automatically.
- They load again when the service returns.
This prevents a plugin from calling a service that no longer exists.
Service isolation
cordis.yml can isolate services so separate plugin groups see separate instances of the same service:
- id: group-a
name: '@cordisjs/plugin-group'
group: true
isolate:
bash: true
config:
- name: '@deepseek-ai/dsh-bash-local'
config:
timeoutMs: 5000
- name: './src/plugin-a.ts'
- id: group-b
name: '@cordisjs/plugin-group'
group: true
isolate:
bash: true
config:
- name: '@deepseek-ai/dsh-bash-local'
config:
timeoutMs: 60000
- name: './src/plugin-b.ts'
plugin-a and plugin-b each see the Bash instance in their own group, with no cross-group effect.
Built-in Harness services
The repository generates the service names, public methods, and source locations into each service's subsystem page. Use those generated regions and the service's TypeScript interface while developing a plugin; do not maintain a second static list.
Next steps
- Event system — communicate between plugins without tight coupling
- Capability layering — use services as capability interfaces