v0.12.3: measured region, shutdown paths, and bind failures

measured region, shutdown paths, and bind failures

• Telemetry records a post-handler failure — output-schema validation, format(), the enrichment merge, the trailer render — as a failed call, not a successful one (#346)
• Stdin EOF runs the shutdown a signal runs, then exits explicitly, so the OTel export leaves the process (#322)
• Logger.close() bounds each pino flush, so a callback that never arrives no longer hangs shutdown (#342)
• An async HTTP bind failure reaches the retry ladder instead of crashing after a success log (#315)
• api-telemetry 1.7 and api-config 1.13 document the new behavior; package.json description synced to the README tagline
• deps: Bun base-image and packageManager pins 1.3.14 → 1.4.0 (#361)

CHANGELOG v0.12.3

v0.12.2: cache hints and x-mcp-header input designation

cache hints and x-mcp-header input designation

• createApp({ cacheHints }) and a per-resource cacheHint set ttlMs / cacheScope on the 2026-07-28 cacheable results (#359)
• headerParam(schema, 'Name') mirrors a tool input property onto an Mcp-Param-Name request header; an illegal placement is rejected at definition time and by the new header-param-designation lint rule (#360)
• transport.sessionMode advertises the resolved mode instead of the configured auto, and narrows to 'stateful' | 'stateless' (#357)
• Shipped skills: add-resource 1.5, add-tool 2.20, api-config 1.12, api-linter 1.12
• deps: openai ^7.4.0 → ^7.5.0 (dev)

CHANGELOG v0.12.2

v0.12.1: SDK v2 migration Phase 2

SDK v2 migration Phase 2

• Tool input accepts a z.discriminatedUnion() of object variants — mutually exclusive argument sets advertise as oneOf branches, each with its own required list and const discriminator (#142)
• ctx.notify* routes per protocol era, and core.notify / createApp({ eventBus }) carry out-of-request emission to 2026-07-28 subscriptions/listen streams (#193)
• Stateful HTTP replays a dropped SSE stream on Last-Event-ID from a bounded per-session event store; on by default, MCP_HTTP_RESUMABILITY=false disables it (#215)
• Handler ctx.traceId / ctx.spanId name the tool_execution:* / resource_read:* span the handler runs in, on every transport (#296)
• New strict-mode linter rule schema-root-oneof-portability; seven shipped skills bumped

CHANGELOG v0.12.1

v0.12.0: MCP SDK v2 and protocol revision 2026-07-28

MCP SDK v2 and protocol revision 2026-07-28

• @modelcontextprotocol/server + @modelcontextprotocol/client replace @modelcontextprotocol/sdk and @hono/mcp; every HTTP endpoint serves revision 2026-07-28 alongside the negotiated 2025 era (#305)
• ctx.requestInput(spec) and ctx.inputs replace ctx.elicit — one handler serves both eras, with expectInputRequired and createMockContext({ inputResponses, requestState }) for driving the re-entry round
• Context extends RequestContext and RequestContext is closed — extra plus withExtra(ctx, fields) replace the removed index signature (#110)
• The experimental tasks surface is gone upstream: task: true, TaskManager, ctx.progress, the tasks capability, the ./tasks subpath, and TASK_STORE_*
• Tool inputs are strict — an undeclared argument key is rejected by name, and inputSchema advertises additionalProperties: false (#232)
• The advertised outputSchema declares the error envelope, and tool() rejects an error field on output or enrichment (#241)
• resources: { subscribe: true } is advertised and backed, and ctx.notifyResourceUpdated(uri) reaches 2026-era clients (#354)
• ctx.log also emits notifications/message, gated by the client's logging/setLevel
• Advertised JSON Schema is 2020-12, and prompt() argument requiredness follows the emitted schema (#258)
• A handler ctx no longer leaks through service errors — both the error and log sinks project to RequestContext via the new toCanonicalContext before serializing
• Also fixed: flat path: message validation text (#66), -32602 for an unknown tool, 415 on a non-JSON Content-Type, a refined output schema registering again, operation and extra carried onto the handler context, an input_required round no longer counted as a failure, and handler notifications reaching every transport
• Internal: skills and telemetry docs refreshed for SDK v2, the task-handler duck-type dropped from definition discovery, Biome config schema synced to 2.5.8
• Upgrading: swap the SDK imports, delete task tools, rewrite ctx.elicit calls, rename any error output field — the changelog entry lists the ordered steps
• deps: openai peer widens to ^6.48.0 || ^7.0.0, nanoid pinned in overrides, and dev-dep bumps clear the transitive undici advisory

CHANGELOG v0.12.0

v0.11.5: server requests across stateful HTTP sessions

server requests across stateful HTTP sessions

• ctx.elicit completes over stateful Streamable HTTP: server-initiated requests carry a session-unique wire ID, so a response arriving on a later POST reaches the Server awaiting it
• A terminated or stale HTTP session settles its pending server requests with a ConnectionClosed error
• .github/ community-health files (CONTRIBUTING.md, CODE_OF_CONDUCT.md, SECURITY.md) now scaffold with init
• bun run test:package typechecks, builds, and tests a scaffold installed offline from the packed tarball
• Skills: api-canvas 2.1 (dataframe trio ships together), design-mcp-server 2.21 (name-scope honesty), git-wrapup 1.10 and the changelog template (authoring length ceiling)
• Repo hygiene: linter and mock-context test coverage, blank issues enabled, security contact moved to security@caseyjhand.com

CHANGELOG v0.11.5

v0.11.4: linter false-negative closures, trailer layout, scaffold gates

linter false-negative closures, trailer layout, scaffold gates

• Linter findings are build-time only — a server carrying a latent gap goes red on its next lint:mcp/devcheck; nothing already deployed changes behavior
• New schema-unsatisfiable error rule: an emitted schema node with an empty value set, commonly z.enum() handed a non-string array (#310)
• format-parity now reaches definitions it skipped — multi-value z.literal([...]) walks, the string sentinel survives markdown escaping, enum/literal/boolean leaves must render as a delimited token, and a subtree past depth 8 warns instead of passing (#310 #337 #282 #280)
• capped-list-no-truncation matches cap names by shape, so maxRecords-style caps are evaluated for the first time (#278)
• Enrichment trailer fields after a notice or a bullet render as their own block rather than folding into it (#308)
• outlineOnOverflow's default notice names the largest section that fits the budget, with its size inline; OutlineOptions.notice takes (sections, budget) (#328)
• Scaffold and image: tsconfig splits typecheck from emit so tests/ is checked, fast-check joins the devDependencies, and both Docker installs carry --omit=peer (#316 #317)
• scripts/tree.ts honors directory-only gitignore patterns, and the fuzz leak heuristic no longer flags the input echoed back in error data (#304)

CHANGELOG v0.11.4

v0.11.3: Opt-in input ceilings, an exchange-wide fetch deadline, and a mock context on real storage

Opt-in input ceilings, an exchange-wide fetch deadline, and a mock context on real storage

• Input ceilings are opt-in again: parsers unbounded without maxBytes, sqliteMirrorStore enforcing only declared limits, StorageService batch caps dropped (#338)
• Parse failures carry the library diagnostic beside the stable data.reason (#339)
• fetchWithTimeout timeoutMs bounds the whole exchange — a 2xx body streams under the deadline through a passthrough wrapper (#341)
• Over-budget error bodies are captured head and tail around an elision marker, with an errorBodyLimit option (#298)
• /utils context parameters accept the handler Context (#297)
• createMockContext state runs the production StorageService, and it and createMockSession are generic over a definition's error contract (#329) (#331)
• normalizeLogLevelAlias removed from /config; .github/workflows/ci.yml removed (#340)

CHANGELOG v0.11.3

v0.11.2: HTTP protocol session, input hardening, package verification

HTTP protocol session, input hardening, package verification

• Elicitation and cancellation work over Streamable HTTP — client capabilities and in-flight requests are carried on the session rather than the per-request SDK server (#312, #311)
• MCP_HTTP_MAX_BODY_BYTES is stream-enforced, so a body with no Content-Length is cut off at the cap instead of buffered whole (#244)
• SSRF blocking replaces its pattern tables with full non-global IPv4/IPv6 range checks; :: was previously reachable (#314)
• Parsers bound their input (1 MiB text, 25 MiB binary) and no longer echo library messages, stacks, or content samples into client-facing error data (#306)
• Storage batches, mirror queries, and DuckDB query bounds are capped; DuckDB exports reject symlinked destinations
• New verification lanes: hermetic published-tarball check, public-export contract, shuffled-order and assertion-required runs, and a GitHub Actions matrix
• Smaller fixes: shutdown and startup rollback, WWW-Authenticate public URL, Worker log-level aliases and error rethrow, in-memory tenant accounting, fuzz leak reporting
• deps: hono ^4.12.32 → ^4.13.1; overrides pin fast-uri ^3.1.5 and add ip-address ^10.3.1, clearing three advisories (#325)

CHANGELOG v0.11.2

v0.11.1: test kit, fuzz generator fixes

test kit, fuzz generator fixes

• createMockSession, createFetchMock, and runToolContract in /testing; toolContractSuite plus session and fetchMock fixtures in /testing/vitest
• zodToArbitrary expands finite nesting in full instead of replacing nodes past depth six with null (#319)
• zodToArbitrary honors .min(), .max(), .length(), and .nonempty() on Zod 4 arrays (#320)
• fuzzTool and fuzzResource treat a thrown McpError as a handled outcome, still leak-checked
• init scaffolds smoke, integration, and fuzz suites with the matching vitest projects and a test:coverage script
• coverage thresholds 94/94/87/94; api-testing and security-pass skills at 1.6; package description synced with the README
• deps: @modelcontextprotocol/sdk ^1.29.0 → ^1.30.0 (plus hono, jose, and dev-dep bumps)

CHANGELOG v0.11.1

v0.11.0: typescript 7, raised peer floors

typescript 7, raised peer floors

• Breaking: optional peerDependencies floors move to the versions this release resolves — a consuming server that installs an affected peer must raise its own range
• TypeScript 7 drives typecheck, typecheck:scripts, and the build; templates/package.json scaffolds new servers on it
• scripts/audit-open-index-signatures.ts holds the TypeScript 6 parser through a typescript-v6 alias — TypeScript 7 dropped the programmatic compiler API
• check-dependency-specifiers scans overrides under the strict rule, so a pin cannot silently re-resolve
• docs:generate is non-functional until typedoc supports TypeScript 7
• new overrides block pins six transitives; biome.json $schema follows the CLI to 2.5.5
• deps: typescript ^6.0.3 → ^7.0.2, better-sqlite3 ^12.11.1 → ^13.0.1, execa ^9.6.1 → ^10.0.0, @opentelemetry/* ^0.220.0 → ^0.221.0 (full arrows in the changelog)

CHANGELOG v0.11.0