[lidge-jun]

GOAT advertises full MCP codec schemas, repeating safe-integer bounds, tagged-object shapes and JSON-string fallbacks in agent context. This compacts the advertised inputs while keeping the full runtime codecs and every existing GOAT tool.

Upstream commit	Upstream PR	Verdict	What GOAT got
ed44f251d89d4dae2f8dcf11c24fb3dec9dda4c7	pingdotgg/t3code#25423	adapt	Schema compaction for image and screen tools, plus PR-report guidance for delegated children, including already-linked PRs.
bc813670d9c428fa42707a0d78c01e03177016ba	pingdotgg/t3code#25790	adapt	Compact inputs for all registered tools through GOAT's common registration wrapper.

GOAT adjustments

• Compact descriptors at McpHttpServer.ts:1070, after admission captures the full schema. Canonical and legacy names, strict codecs, unknown-argument refusal, analytics, idempotency, access declarations and screen-code hooks stay on their existing paths.
• Preserve optional and required nulls, JSON literal data, explicit limits and schema-valued records; retain JSON-string inputs when no native object or array alternative exists. Deduplicate union branches and merge only required string discriminators.
• The existing catalog tests verify all 215 registry entries and their access behavior. Added registration coverage proves a compact union still rejects a missing branch field and an unknown argument before its handler runs.
• Web, desktop, mobile and every provider consume the same MCP server; no client, provider-adapter or packages/contracts edits are needed. No visible UI changed.

GOAT's own context measurement, using its served catalog (same tool counts before/after):

Measurement	Before	After	Reduction
Default core model-facing listing (2 tools)	2,226 B	2,226 B	0.0%
Full model-facing listing (212 tools available to the measured caller)	211,848 B	199,502 B	5.8%
Full input schemas	141,002 B	128,656 B	8.8%

The existing core budget passes for every measured harness. The full listing remains a diagnostic measurement, outside the default core budget; no new upstream context snapshot or second CI ratchet was added.

Not taken

Upstream's consolidation of 18 tools into action tools and the accompanying handler, prompt, mobile and presentation rewrites were excluded. GOAT keeps its registry-backed canonical paths, compatibility aliases, per-action grants, delegated-task behavior and screen-code registration. Both assigned commits were adapted; neither was omitted wholesale.

Rename residue

git show <sha> | rg '^\+.*\b[Tt]3' was inspected for both commits. From ed44f251d8, all added branded names occur in excluded hunks: T3, T3McpToolSummaryAction, T3_MCP_TOOLS, T3_MCP_TOOL_NAMES, t3Action, t3McpToolPresentation, t3ToolSummaryCall, t3_pending_request, t3_pending_request_, t3_queue, t3_queue_, t3_thread_configure, t3_thread_fork, t3_thread_merge_back, t3_thread_send, t3_thread_transfer, t3_thread_transfers, t3code, and t3tools. This includes the old helper comment and T3 Connect wording, neither of which was imported. resolveT3McpSummaryAction and resolveT3McpToolDefinition also belong to excluded presentation hunks. bc813670d9 adds no matching names. No new rename rule or retained branded identifier was needed.

Initial implementation verification (e8909bc)

• Red before the fix: both child PR-link cases failed because next was absent; the catalog compaction case failed on the full goat_html_render schema; the tagged registration case failed on the unmerged union.
• lockf -k /tmp/goat-heavy-check.lock vp test run apps/server/src/mcp/advertisedJsonSchema.test.ts apps/server/src/mcp/toolkits/pullRequests/handlers.test.ts apps/server/src/mcp/toolkits/screen/tools.test.ts apps/server/src/mcp/toolkits/screen/handlers.test.ts — exit 0, 4 files / 26 tests passed.
• vp env exec node scripts/agent-surface/context-budget.ts --json --check — exit 0; all core budgets pass. --listing full --json — exit 0; measurements above.
• node scripts/goat-rename.ts --check — exit 0, zero residue and zero dropped paths.
• git diff --check — exit 0. Source-diff privacy scan found no local identity, session, workspace or credential strings.
• lockf -k /tmp/goat-heavy-check.lock vp test run apps/server/src/mcp/advertisedJsonSchema.test.ts apps/server/src/mcp/advertisedJsonSchema.registration.test.ts apps/server/src/mcp/McpHttpServer.test.ts apps/server/src/mcp/agentSurface.test.ts apps/server/src/mcp/toolListing.test.ts apps/server/src/mcp/ToolAdmission.test.ts apps/server/src/mcp/McpToolAccess.test.ts apps/server/src/mcp/McpToolAccess.capabilities.test.ts apps/server/src/mcp/toolkits/pullRequests/handlers.test.ts apps/server/src/mcp/toolkits/screen/tools.test.ts apps/server/src/mcp/toolkits/screen/handlers.test.ts — exit 0, 11 files, 197 passed, zero failed, one existing TODO for goat_eval (Agent surface verification: conformance cases waiting on goat_call, goat_eval, goat_describe and handoff wait #778).
• lockf -k /tmp/goat-heavy-check.lock vp test run apps/server/src/mcp/harnessListing.test.ts apps/server/src/mcp/computerUseRequestSchema.test.ts — exit 0, 2 files / 8 tests passed. The initial changed-file gate exposed old nullable foreground advertising assertions; these initially asserted the compact boolean. Review round 1 below restores the nullable advertisement; runtime null/boolean/invalid-type checks remain intact.
• Runtime registration transcript from the contract test: a URL branch without url fails decoding; a valid target plus unknown typo is refused before the handler; {target:{kind:"number",number:1}} reaches the handler. HTTP computer-use calls accept null as omission and reject invalid foreground types through both direct calls and goat_call.
• lockf -k /tmp/goat-heavy-check.lock vp run check:changed — exit 0 on e8909bc: format, lint, both knip passes, GraphQL generation and both affected-package typechecks pass; 55 test files pass, 1,212 tests pass, zero fail, three existing skips and one existing TODO. Existing lint warnings remain. Complete output was inspected, with non-error compiler suggestions counted separately.

Review round 1

• Major finding 1 — fixed in 57ef6d3: preserve every nullable alternative, including provider.update.displayName and accentColor, rather than inferring null-as-omission from optionality. Nullable tagged-object inputs still compact their object branches. The full 215-entry catalog audit found 686 lost nullable paths before the fix, including nested fields, and none afterward; raw image and screen registrations are included.

• Both new regression tests failed against the reviewed compactor. The real provider registration's HTTP tools/list and goat_describe schemas now retain clearing; direct calls and goat_call preserve omitted/custom/null values and refuse invalid types and unknown arguments without reaching the service.

• Focused verification: vp test run apps/server/src/mcp/advertisedJsonSchema.test.ts apps/server/src/mcp/advertisedJsonSchema.registration.test.ts apps/server/src/mcp/computerUseRequestSchema.test.ts apps/server/src/mcp/agentSurface.test.ts apps/server/src/mcp/harnessListing.test.ts apps/server/src/mcp/toolkits/screen/tools.test.ts apps/server/src/mcp/toolkits/screen/handlers.test.ts apps/server/src/mcp/toolkits/provider/handlers.test.ts — exit 0, 8 files / 52 passed / zero failed / one existing TODO.

• node scripts/goat-rename.ts --check and git diff --check — exit 0. vp env exec node scripts/agent-surface/context-budget.ts --json --check — exit 0; core budgets pass. Fresh full-listing measurements above replace the pre-review numbers; preserving null intentionally gives up some compaction.

• lockf -k /tmp/goat-heavy-check.lock vp run check:changed — exit 0 on 57ef6d3a6a3d303bd79cd97b2167ec80522ec2da: format, lint, both knip passes, GraphQL generation and both affected-package typechecks pass; 55 test files / 1,214 tests pass, zero fail, three existing skips and one existing TODO. Existing lint warnings and advisory compiler suggestions remain. The working tree is clean; the runner declined to cache because its inputs changed during the run.

NOT RUN: repo-wide checks and UI/dev-server smoke (no visible change); CI completion (handed back without watching or merging).

Model: gpt-6.1-sol via GOAT delegated task (Codex harness)