## Why
Rendering host and executor skill catalogs independently allows their combined
metadata to exceed the skills context budget.
## What changed
- Allocate one budget across both catalogs when both contain model-visible
skills.
- Prefer retaining executor skills when budget pressure requires omissions,
while preserving an executor omission marker and reporting when all host
skills were omitted.
- Evaluate absolute and aliased host paths under the shared budget and select
the rendering that best preserves executor entries, total entries, and
descriptions, in that order.
## Testing
Added renderer and production-turn coverage for shared-budget description
shortening, host-first omission, executor omission markers, and alias selection.
GitOrigin-RevId: 30041736a76aa173cb641aa98a876a306cb437d2
## Why
Host skill catalogs supplied through extension world state should report budget warnings only when their catalog update is actually rendered.
## What changed
- Stop rebuilding an extension-owned host catalog in core.
- Emit host catalog budget warnings when the corresponding world-state fragment is rendered, and deduplicate them with executor catalog warnings.
- Cover full, shortened, and omitted host and executor catalogs, including repeated turns and resumed persisted snapshots.
GitOrigin-RevId: ba28b6e337281b49ed4da2175c193fd4a6898ab7
## Why
Empty rendered skill catalogs skipped catalog telemetry instead of reporting
zero-valued counts.
## What changed
- Record a default render report when thread, turn-input, or executor catalog
rendering produces no fragment.
- Record zero-valued host world-state metrics when skill instructions are
enabled but no host skills are available.
- Preserve the `catalog_surface` tag so empty host and executor catalogs remain
distinguishable.
## Testing
Add coverage for empty catalog rendering and mixed nonempty-executor,
empty-host world state.
GitOrigin-RevId: f68d65806703c0ded1ece1e5ae1ffaf6d6045126
## What changed
- Add an optional `ExtensionMetrics` capability to thread, turn-input, and world-state contributors, backed by session telemetry in the host.
- Record skill counts, omissions, and truncated description characters for extension-rendered catalogs, tagged by the catalog surface.
- Preserve host session attribution on extension metrics, including the effective model for each turn, and prevent extension tags from overriding host metadata.
- Avoid duplicate host-catalog samples by recording world-state metrics only when the section is published or changes.
## Testing
- Cover metric values and surface tags, session metadata preservation, turn-level model changes, and host world-state publication behavior.
GitOrigin-RevId: 9059e521943a8f81df25a38b03692eddbc1d990d
## Why
Skill catalog rendering can shorten descriptions or omit enabled skills to fit
the model context budget. Surface these reductions so users know when the
model-visible catalog has lost detail.
## What changed
- Emit a warning with the omitted skill count whenever entries do not fit.
- Warn when description shortening averages more than 100 characters per skill.
- Deduplicate executor catalog warnings across repeated world-state builds in a
turn.
## Testing
- Cover the description-shortening threshold and omission warning text.
- Verify warnings through extension and production-turn catalogs, including
per-turn deduplication.
GitOrigin-RevId: bd7fc3482e5dfd8c79072f772a2f54aa502478d9
## Why
A fixed character limit does not account for the different context-window sizes supported by models.
## What changed
- Budget extension-rendered skill metadata at 2% of the resolved model context window, capped at 4,000 tokens.
- Keep the existing 8,000-character fallback when model context metadata is unavailable.
- Include the omission marker in the budget and still emit it when no skill entry fits.
- Apply the same resolved budget to executor and host skill catalogs assembled for a turn.
## Testing
- Cover proportional and capped budgets, multibyte fallback accounting, and omission-marker behavior.
- Verify through the production turn path that larger model context windows include more catalog entries without exceeding the computed budget.
GitOrigin-RevId: 4667293f1594de4dd605b32b9fa4255d26772c0f
## What changed
- Parameterize skill catalog rendering with explicit core- and extension-compatible description policies.
- Use full skill descriptions for core-compatible output, while extension-compatible output prefers `short_description` and falls back to the full description.
- Keep extension prompt and world-state rendering on the extension-compatible policy.
## Testing
- Add a renderer test covering description selection and fallback for both policies.
GitOrigin-RevId: 5382075f88c25a49a715feb0702a9ab888ec0123
## Why
Host skills can change after a thread starts. Subsequent turns need the updated
catalog without reinjecting an unchanged catalog on every turn.
## What changed
- Register the host skill provider in app-server and project its catalog through
a dedicated World State section.
- Render host skills with the existing metadata budget and usage instructions,
including skill-root aliases when available.
- Suppress the legacy host catalog and contextual fragment when World State owns
the catalog, while preserving host skills for explicit and shadow selection.
## Testing
Added an app-server test that installs a host skill at runtime and verifies the
catalog updates once and remains stable on the following turn.
GitOrigin-RevId: 4cacc6b2258fc3cab8499fbdf9aa6ab0324ec10d
## Summary
- add a false-by-default `include_skills_usage_instructions` model
metadata field
- enable the field for the bundled `gpt-5.5` model metadata
- consume the metadata in both core and extension skill rendering
- remove hardcoded legacy-model matching and its marker plumbing
## Why
World State restores its structured snapshot on resume so unchanged
sections do not have to be rendered again. That is safe only when the
model-visible fragment represented by the snapshot is still present in
retained history.
For selected executor skills, the failing selected-capability scenario
exposed this state:
```text
persisted World State: selected skill catalog is known
retained model history: selected skill catalog message is missing
next diff: unchanged, so emit nothing
```
The model resumes without being told about the selected skill catalog.
## What changed
World State contributions may now optionally describe the concrete
model-visible fragment that must remain in retained history.
When a persisted snapshot is present:
```text
matching retained fragment exists -> trust snapshot, emit nothing
matching retained fragment missing -> treat section as absent, render current state once
```
The skills extension uses this for non-empty selected-environment
catalogs by matching its exact rendered catalog body. Empty or hidden
catalogs do not require a fragment.
## Scope
This does not clear or rebuild the whole World State baseline. It does
not change skill discovery, cache invalidation, environment
availability, or MCP runtime behavior. It only keeps a persisted section
snapshot and its retained model context consistent across resume/history
reconstruction.
## Coverage
A focused World State regression test verifies both sides:
- a missing retained fragment is rendered again
- a matching retained fragment avoids duplicate injection
## Why
A selected executor environment can be unavailable in one model step and
ready in the next. The model should see its skills only while that
environment is ready, without rescanning stable files on every sample.
The product assumption is simple:
- an environment ID names one stable logical environment;
- the selected root contents do not change during the thread.
## Behavior
```text
E1 unavailable -> do not show E1 skills
E1 ready -> discover once, cache, show through World State
E1 unavailable -> hide skills, keep cache
E1 ready again -> reuse cache, show skills again
resume -> create a new thread cache and discover again
```
The cache key is the full `SelectedCapabilityRoot`. Availability does
not invalidate it; dropping the extension's thread state does.
The step supplies the ready selected roots directly. They do not have to
be turn environments:
```text
turn environment: laptop
selected root: worker:/plugins/lint-fix
worker ready -> lint-fix skills are visible
```
## What changes
- Keeps executor skill catalogs in the existing skills extension.
- Passes the roots resolved as ready for the step into World State
contributors.
- Loads each ready selected root at most once per thread.
- Contributes the executor catalog as the `skills` World State section.
- Uses the exact step catalog for explicit skill selection and body
reads.
- Leaves host and orchestrator skill behavior where it already lives.
Taking a step snapshot itself does not add an RPC. Executor filesystem
calls happen only on the first discovery of a stable root for that
thread.
## What does not change
- No filesystem watcher or content-based invalidation.
- No retry/generation framework.
- No skill runtime migration into core.
- No general rewrite of the skills extension.
## Stack
1. Extension-owned World State sections.
2. **This PR:** project cached executor skills through World State.
3. Pin one MCP runtime to each model step.
4. Project selected MCP/app/connector metadata by environment
availability.
5. One end-to-end integration scenario.
felixxia-oai