Reduce Mcp Tool Surface Footprint

Why

The hosted MCP surface currently repeats the same cross-cutting guidance across many tool descriptions, producing a ~49.6 KB tools/list payload for 14 tools. That cost is paid by every MCP client session and sits in an unpredictable zone for chat-hosted clients whose exact tool-description and tool-result budgets are host-defined.

Official MCP and OpenAI guidance provides a cleaner path: use server instructions for cross-tool guidance, keep tool descriptions concise and routing-specific, and keep model-visible tool results bounded by default.

What Changes

• Add compact MCP server instructions for shared PDPP tool-use rules (connection_id, typed filters, schema-first discovery, event-subscription preflight, and pagination).
• Shorten repeated per-tool descriptions and field descriptions without weakening validation or REST forwarding semantics.
• Keep event-subscription delivery/signing details in the capability-discovery tool and replace repeated lifecycle footers on CRUD tools with a short pointer.
• Add regression coverage that measures the default tools/list payload and prevents reintroducing duplicated long descriptions.
• Preserve the current tool names and all existing read/event-subscription capabilities in this tranche.
• Defer non-standard lazy/deferred tool loading and advanced result-detail changes until host behavior is proven by controlled tests.

Capabilities

New Capabilities

• None.

Modified Capabilities

• mcp-adapter: hosted and stdio MCP surfaces publish compact server instructions and avoid duplicated model-visible tool-definition prose while preserving grant-scoped read behavior.

Impact

• Affected package: packages/mcp-server.
• Affected tests: MCP server/tool schema tests.
• No REST contract changes, storage changes, grant semantics changes, connector changes, or dependency changes.