fix(mcp-apps): SEP-1865 capability declaration + content/structuredContent split

[asachs01]

SEP-1865 compliance backport (mechanical)

Part of a fleet-wide mechanical SEP-1865 compliance backport across WYRE-AI MCP servers. A compliance audit found zero MUST-level violations but two consistent SHOULD-level gaps. This PR closes both for syncro-mcp, touching only the capability declaration and the content/structuredContent split for the card-attached tool. No refactors, no dependency bumps, no card-building logic changes.

1. Explicit io.modelcontextprotocol/ui capability declaration

Per the ext-apps spec's Capability Negotiation section, servers negotiate MCP Apps support via the standard extensions capability mechanism (SEP-1724). syncro-mcp was not declaring this, relying on implicit support.

Before (src/mcp-server.ts):

capabilities: {
  tools: {},
  resources: {},
},

After:

capabilities: {
  tools: {},
  resources: {},
  extensions: {
    "io.modelcontextprotocol/ui": {
      mimeTypes: ["text/html;profile=mcp-app"],
    },
  },
},

2. content/structuredContent separation

syncro_tickets_get previously JSON-stringified the entire ticket payload (including the _card UI attachment) into a single content text block. SEP-1865 expects content to carry a human-readable summary and structuredContent to carry the machine-readable payload.

Before (src/domains/tickets.ts):

return {
  content: [{ type: "text", text: JSON.stringify(payload, null, 2) }],
};

After:

const summary = `Ticket #${ticket.number ?? ticket.id} (${
  ticket.status ?? "unknown status"
}): ${ticket.subject ?? "no subject"}`;

return {
  content: [{ type: "text", text: summary }],
  structuredContent: payload,
};

payload (ticket data + _card when present) moves to structuredContent; content now carries a concise one-line summary instead of a JSON dump.

Tests updated

• tests/domains/tickets.test.ts — syncro_tickets_get test now asserts on structuredContent instead of parsing content[0].text as JSON.
• tests/mcp-apps.test.ts — added:
  • a test asserting content is plain text (not JSON-parseable) and contains the summary, while structuredContent carries the full payload.
  • a test asserting the server declares io.modelcontextprotocol/ui in capabilities.extensions.

Test output (real, from this branch)

> @wyre-ai/syncro-mcp@1.1.6 test
> vitest run

 RUN  v5.0.0 /Users/asachs/work/syncro-mcp

 Test Files  15 passed (15)
      Tests  163 passed (163)
   Start at  21:07:37
   Duration  517ms (transform 61%, import 25%, tests 10%, worker 4%)

Build output

> @wyre-ai/syncro-mcp@1.1.6 build
> tsc

(clean, no errors, no output — tsc succeeded)

No pre-existing test failures encountered; full suite is green before and after.

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Summary by CodeRabbit

• New Features
  • Ticket retrieval now provides a concise, readable summary with the ticket number, status, and subject.
  • Complete ticket details remain available in structured data for supported integrations.
  • Added support for displaying HTML-based MCP Apps content through compatible interfaces.

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📥 Commits

Reviewing files that changed from the base of the PR and between 885d29e and 244f160.

📒 Files selected for processing (4)

• src/domains/tickets.ts
• src/mcp-server.ts
• tests/domains/tickets.test.ts
• tests/mcp-apps.test.ts

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📝 Walkthrough

Walkthrough

The ticket-get operation now returns concise text and exposes the full ticket payload through structuredContent. The MCP server declares the MCP Apps UI extension and supports text/html;profile=mcp-app. Tests cover both contracts.

Changes

MCP Apps support

Layer / File(s)	Summary
Ticket response contract src/domains/tickets.ts, tests/domains/tickets.test.ts, tests/mcp-apps.test.ts	Ticket retrieval returns text containing the ticket number, status, and subject. The full payload remains in structuredContent. Tests validate both representations.
MCP Apps capability declaration src/mcp-server.ts, tests/mcp-apps.test.ts	createMcpServer declares io.modelcontextprotocol/ui and supports text/html;profile=mcp-app.

Priority: ⬇️ Low

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

Change: Bug fix

Suggested reviewers: arutherford

Merge Risk: ⚪ Minimal · up to 244f1

The ticket response and MCP Apps capability declaration preserve their intended client contracts. No actionable merge risk remains.

🚥 Pre-merge checks | ✅ 5 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Changelog Entry	⚠️ Warning	The PR changes runtime behavior in src/domains/tickets.ts: syncro_tickets_get now returns a human-readable content summary and moves the full payload to structuredContent. It also adds the pub…	Add a changelog entry under ## [Unreleased], in ### Changed, for the syncro_tickets_get content/structuredContent response change and the MCP Apps capability declaration.

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely identifies the two main changes: the MCP Apps capability declaration and the separation of human-readable content from structured content.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 2 functions across 4 files.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

Full details: Changelog Entry

Explanation

The PR changes runtime behavior in src/domains/tickets.ts: syncro_tickets_get now returns a human-readable content summary and moves the full payload to structuredContent. It also adds the public io.modelcontextprotocol/ui capability declaration in src/mcp-server.ts. The PR changes no CHANGELOG.md file; the base and head changelog objects are identical. Therefore, it adds no corresponding entry under ## [Unreleased].

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