[anycodes]

Description

The managed Agents API rejects the optional canonical type: "message" on otherwise supported user text input. Explicit false-like Agent IDs can also bypass lookup, and quota/unavailable errors use the generic invalid-request category.

Accept the typed text form, validate explicitly supplied IDs without coercion or truthiness fallback, and distinguish the two directly evidenced error categories. Preserve saved-Agent plus inline overrides and copied Session settings.

Refs #162
Related delivery: Alibaba-Agent-Sandbox/awesome-templates#309

Type of Change

• Bug fix
• Documentation
• Tests

Changes

• Keep input types/byte limits and owner-aware404 behavior; reject invalid inputs before durable writes.
• Add typed Session/event/Submission and real HTTP regressions, saved-Agent snapshot/override coverage, and SQLite/temporary PostgreSQL checks.
• Update both API guides, changelog and repository-owned proposed decision/evidence. Documentation explicitly requires an updated Gateway for the new input behavior.

Testing

• make test: server875 passed/1 skipped; client2483 passed/27 skipped.
• make ci: lint, format, typecheck, hygiene, tests, paired builds, distribution and fresh-install checks passed.
• After adding the build-system dependency, targeted packaging modules passed (server5/client7); the other26 skipped tests need existing cross-repository Node/engine prerequisites and are not counted as passes.
• Actual temporary PostgreSQL and local HTTP tests passed; fake Agent fixtures do not prove cloud/model business acceptance.
• Repository health:106 passed, one existing release-runbook warning, no failures. Staged secret and diff checks passed.

Definition of Done

• Regressions, bilingual docs, changelog, proposed ADR and dated verification.
• Real-cloud/model acceptance for this candidate.
• Remote CI/review on the current head.

This PR stays Draft until required product gates are complete. It does not complete YAML v1 consumers/templates, new Agent support, full OpenAI SDK compatibility, package publication, or the later blogs/Registry topic. No cloud resources were created by these checks. Earlier missing-pip environment failure and its correction remain in the verification history.