Choose an interface that matches the product
A web app does not become agent-invocable merely by adding an llms.txt file. Invocation requires an actual interface: an MCP server, a documented API, an agent card for a compatible agent, or another client-supported mechanism.
Do not advertise a transport until it is live. Deploy to Agents can audit public surfaces and exposes its own remote MCP endpoint; it does not claim to convert an arbitrary API into a working MCP server automatically.
Describe tools for correct selection
Tool names and descriptions should identify the user job, required inputs, meaningful output, side effects, and constraints. Schemas should reject ambiguous input instead of relying on prose. Read-only and destructive operations should be distinguishable.
Keep the public listing, live tool inventory, documentation, and repository aligned. A directory description cannot repair a stale schema, and a healthy handshake does not prove completion of a useful task.
Test invocation as a sequence
Verify transport negotiation, initialization, tool enumeration, schema validation, authorization boundaries, execution, and output interpretation. Record each stage so a retrieval success is not reported as task success.
A strong invocation receipt names the client, endpoint, tool, sanitized inputs, result class, time, and failure boundary. Production claims should come from those receipts, not from an MCP badge.