[EtanHey]

Size: XS

Problem

OrchestratorMcpTarget.providerInstanceId has a description in source ("Provider instance id from orchestrator_capabilities."), but agents never see it: tools/list sends delegate_task.target.providerInstanceId and create_threads.threads[].target.providerInstanceId as a bare {"type":"string"}. ProviderInstanceId decodes through a transform (a trimmed, branded string). JSON Schema documents a transform's encoded side, and .annotate() writes to the decoded side, so the text is dropped.

Change

The field now uses Schema.annotateEncoded, so agents see From orchestrator_capabilities.. The existing target-options description is shortened while retaining inheritance and clearing semantics. Decoding is unchanged.

This restores the provider-instance guidance used by delegate_task and create_threads without increasing the total advertised tool-list size.

Scope and approval

No issue: a small fix for an existing description that the schema-advertising path drops.

Measured against main 37481f0, the tool list decreases from 47,818 to 47,814 bytes (−4). agentContextBudget.json records that exact size; no context-increase approval is required for this version.

Verification

• Failing first: apps/server/src/mcp/toolkits/orchestrator/tools.test.ts "tells agents where a target's providerInstanceId comes from" checks the advertised schema (the same advertisedJsonSchema that McpHttpServer serves) for both delegate_task.target and create_threads.threads[].target. On main it fails with expected undefined to be 'From orchestrator_capabilities.'; with the fix it passes.
• At 4e87685, vp run check:changed 37481f044e749a658d94a927b33b268a733f94c5 passes for the three feature files, including six focused tests. A fresh independent review reran the exact budget test (two tests pass) and verified the unchanged feature patches and merge history. Hosted CI is tracked separately.

The following model evals are historical evidence for the earlier 182b27b7d9 variant. They were not rerun after the later description shortening or this mechanical integration; they are not current-head model-eval proof.

• Eval evals/mcp-tool-use, baseline main (79f1fadfc6) vs this branch (182b27b7d9), both clean checkouts, 3 samples per case. Touched cases: cross-provider-delegates-with-options, same-provider-delegate-with-effort, delegate-runtime-mode-narrowed, guard-capabilities-recheck-after-provider-returns, delegates-then-new-thread-with-model, restart-delegate-with-full-access. Controls: control-diff-question-no-thread-id, control-fix-failing-tests.
  • Claude Sonnet 5.5: 24/24 baseline, 24/24 candidate.
  • GPT-6.1 Sol (OpenAI API directly): 24/24 baseline, 24/24 candidate.
  • No touched case fails on main, so the eval shows no regression, not an improvement.
• Full suite, per evals/README.md (one full run per model; 2 samples per case; a case passes when more than half its samples pass). Main 79f1fadfc6 was run alongside, from clean checkouts with pinned heads. Sonnet 5.5 runs 112 cases; GPT-6.1 Sol runs 108 (5 cases are Claude-harness-only, 1 Codex-only). Every case that went from 2/2 on main to 1/2 or 0/2 here was re-sampled 4 more times on both sides (6 total per side).
  • Sonnet 5.5: 101/112 here vs 104/112 on main. Re-sampled flips: ORC-01 6/6 → 5/6, opus-review-too-via-delegate 5/6 → 5/6, review-followup-ask-sol-to-confirm 5/6 → 4/6, thread-mention-without-link-after-read 6/6 → 4/6 (all still pass). DEL-02 went 5/6 → 2/6, then 6/8 → 6/8 on 8 more samples per side (11/14 vs 8/14 overall). None of the 28 DEL-02 samples calls delegate_task or create_threads, the only tools this changes. Net: no regression against main.
  • GPT-6.1 Sol: 103/108 here vs 104/108 on main. Re-sampled flips: child-pushes-existing-pr-links 5/6 → 5/6, requested-after-video-for-edit 5/6 → 5/6. One sample errored after retries (HOST-01a) and is left out. Net: no regression.
  • Cost: Sonnet $10.47 here, $9.94 for main (shared by the three PRs), plus re-samples. GPT runs went to the OpenAI API and are not priced by the eval.
• Not checked: Opus and GPT-6 Astra; a running server's tools/list.

🤖 Original implementation: Claude Opus 5.5; review: GPT-6.1 Sol. Mechanical integration: GPT-6.1 Sol; review: Claude Opus 5.5, in T3 Code Nightly.

Fixes #32850

[macroscopeapp]

Approvability

Verdict: Approved at 182b27b

Macroscope's review found this PR approvable — This makes MCP tool descriptions explain where providerInstanceId comes from and updates the corresponding size baseline. The change is descriptive metadata, with no material change to runtime behavior or product defaults.

^{You can add or adjust custom eligibility rules. Learn more.}

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Walkthrough

The orchestrator target schema updates its provider instance ID and options descriptions. A test checks the advertised provider instance ID descriptions for two tools. The configured MCP tool-list byte count changes.

Changes: Orchestrator schema description

Layer / File(s)	Summary
Encoded description and advertised schema test packages/contracts/src/orchestratorMcp.ts, apps/server/src/mcp/toolkits/orchestrator/tools.test.ts, apps/server/src/provider/agentContextBudget.json	The provider instance ID description is attached to the encoded schema and now reads “From orchestrator_capabilities.” The options description is shortened and retains its stated override and clearing behavior. A test checks the advertised descriptions for delegate_task and create_threads. The configured mcpToolListJsonBytes value changes from 47498 to 47494.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

• pingdotgg/t3code#30808: Adds a scheduled-task target that reuses the schema fields whose descriptions change here.
• pingdotgg/t3code#25785: Adds the budget test and workflow related to the MCP tool-list byte count.
• pingdotgg/t3code#23285: Moves schema annotations to encoded or optional schemas, as this change does for providerInstanceId.

Suggested reviewers: maria-rcks

Merge Risk: Minimal · up to 9f110

The schema change meets its advertised contract, and the current budget does not increase relative to the PR base.

Pre-merge checks: 3 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Description check		The description includes all required sections and gives focused verification details. However, its claim that the tool list shrinks by 4 bytes conflicts with the PR objectives, which report a 96-byte…	Update the description with the tool-list size measured for the current PR head and the correct baseline. If the current change increases the tool-list size, state whether the required agent-context-increase label has been added or obtain t…

Passed checks: 3 passed

Check name	Status	Explanation
Title check		The title clearly identifies the two affected tools and the primary change: documenting where target providerInstanceId values come from.
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

Full details: Description check

Explanation

The description includes all required sections and gives focused verification details. However, its claim that the tool list shrinks by 4 bytes conflicts with the PR objectives, which report a 96-byte increase and say the agent-context-increase label is required. This leaves the reported budget impact and approval status unclear.

Resolution

Update the description with the tool-list size measured for the current PR head and the correct baseline. If the current change increases the tool-list size, state whether the required agent-context-increase label has been added or obtain the required maintainer approval. Align the verification and budget statements with that measurement.

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Files selected for processing: 2

• apps/server/src/provider/agentContextBudget.json
• packages/contracts/src/orchestratorMcp.ts

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• packages/contracts/src/orchestratorMcp.ts

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Actionable comments posted: 1

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Inline comments:
Review comments at @apps/server/src/provider/agentContextBudget.json:
- Line 4: Reduce the advertised text contributing to the `mcpToolListJsonBytes`
budget in `agentContextBudget.json` so the value does not exceed the prior
46109-byte limit; do not change the budget value to accommodate the increase.

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• apps/server/src/mcp/toolkits/orchestrator/tools.test.ts
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[EtanHey]

This makes the tool list 96 bytes longer (47,538 → 47,634), so the agent-context budget check needs the agent-context-increase label from a maintainer. The added bytes say where a target's providerInstanceId comes from. A byte-neutral version would mean cutting other tool text and re-running the paid evals, so I left it as is. Could a maintainer add the label if this looks right?