Fix MCP discovery and Accept compatibility

[Trailgenic]

Motivation

• Restore browser-readable JSON discovery at the canonical MCP root and make the MCP POST transport tolerant of harmless/incomplete Accept headers while preserving all existing security, validation, and SDK behavior.

Description

• Implement Accept compatibility and normalization in app/mcp/route.ts: accept missing/empty, */*, and JSON-only Accept headers, normalize those cases to application/json, text/event-stream, pass fully compliant JSON+SSE requests through unchanged, and reject text/event-stream-only or unsupported types with HTTP 406; normalization clones the incoming Request and changes only the Accept header. (Preserves Content-Type, Origin, MCP-Protocol-Version, session headers, body and all other request properties and continues to call handleEllaMcpPost.)
• Restore browser discovery JSON for https://mcp.ellaentity.ai/ in app/mcp/route.ts, generating discovery values from the canonical registry constants (canonical entity ID, server info, protocol versions, tool names, resource URIs, docs and entity-graph URLs, and a public read-only scope statement) rather than hard-coding values.
• Use a minimal routing approach: keep the existing host-based rewrite but add a marker so root rewrites can be distinguished; next.config.ts rewrites mcp.ellaentity.ai/ -> /mcp?mcpRoot=1, and app/mcp/route.ts treats host mcp.ellaentity.ai + either path / or the mcpRoot=1 marker as the canonical root discovery request; direct GET /mcp remains 405 with Allow: POST, OPTIONS.
• Bump MCP server behavior version in registry from 1.1.2 to 1.1.3 without changing any ontology/entity data, canonical IDs, tool names, resource URIs, data versions, lastModified values, or privacy boundaries.
• Add/update behavioral tests in tests/mcp.test.ts to assert Accept normalization behavior and canonical root discovery and alias behavior.
• Files changed: app/mcp/route.ts, lib/ella-registry.ts, next.config.ts, tests/mcp.test.ts (commit on branch codex/fix-mcp-discovery-and-accept-compatibility, commit id c1ffd68).

Testing

• Ran git diff --check which passed and committed the changes locally; the repository contains the new tests and route logic but cannot be pushed from this environment due to network/proxy restrictions.
• Attempted npm ci but the environment’s proxy/network prevented a successful dependency install, leaving dependencies incomplete and causing subsequent steps to fail.
• npm run lint could not complete due to missing dev dependencies (ESLint modules), therefore lint did not pass in this environment.
• npm run typecheck failed locally because required packages and types (e.g., next, React JSX runtime, zod, MCP SDK types, Node types) were not available after the failed npm ci.
• npm test could not complete because tsx was not installed in node_modules in this environment; tests were added and are runnable in a normal environment and include assertions for: missing Accept, empty Accept, */*, application/json only, application/json, text/event-stream, text/event-stream alone -> 406, text/plain -> 406, invalid Content-Type -> 415, disallowed Origin -> 403, preservation of JSON-RPC body and headers, root discovery JSON contents, /mcp 405 behavior, and alias POST behavior.
• npm run build could not complete locally because next was not available after dependency install failed.
• git push failed in this environment (CONNECT tunnel failed, response 403) so the branch remains pushed only locally and GitHub Actions CI / verify was not run; therefore no Draft PR URL is available from this run.

If CI/network access is available in your environment, run the verification sequence: npm ci, npm run lint, npm run typecheck, npm test, npm run build, and the tests added in tests/mcp.test.ts should validate the Accept normalization and discovery behavior; the change preserves all canonical registry values, tools, resources, protocols, schemas, provenance, and privacy boundaries (only the server version string was incremented to 1.1.3).

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Codex Task

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Project	Deployment	Actions	Updated (UTC)
ellaentity	Ready	Preview, Comment	Jul 14, 2026 2:00am