Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Goes well beyond the annotations, which already declare read-only, idempotent and closed-world. The description adds that the endpoint is public with no sign-in, that it does not authorize an account connection or call the listed APIs, that transport/server failures remain errors, and that HTTP 429 carries Retry-After — all behavior an agent cannot infer from structured fields.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the purpose and use case, then the exclusions, then return shape, then behavioral caveats — a sensible ordering. Some clauses are compressed into run-on semicolon chains ('Transport/server failures remain errors; no marketplace or account lookup is performed'), which slightly hurts scanability but not correctness.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description carries the burden of describing returns and does so ('links for agent access, API catalog, OpenAPI, documentation feeds and REST/MCP OAuth metadata as text'). Combined with auth status and error/rate-limit behavior, an agent has everything needed to invoke this zero-argument tool correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Zero parameters, so the baseline is 4. The description explicitly confirms 'no arguments are needed,' removing any doubt about whether an empty object is acceptable, though there is little else to clarify for an argument-free tool.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource: 'Discover SuperCatch's machine-readable API and authentication specifications.' The scope is further bounded by naming what the catalog contains (OpenAPI, API-catalog, OAuth discovery documents), which separates it from data-fetching siblings such as get_product or list_account_orders.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives a clear trigger ('Use when configuring an API client or finding OpenAPI, API-catalog and OAuth discovery documents') and explicit exclusions ('Card searches, account data and answers from help articles are outside this catalog'). It stops short of naming the sibling tools that handle those excluded cases (e.g. search_public_docs, get_help_resource), so routing is implied rather than directed.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.