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

Annotations only declare readOnlyHint and a closed-world hint; the description adds materially more: no authentication required, the pricing model (USDF base units, cost plus at most 5%), the page size ceiling of 200, and the page.next cursor mechanism. That is exactly the auth, cost, and pagination context an agent cannot get from the annotations.

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?

It is a single dense sentence-cluster, but front-loads the important facts (endpoint, pricing, callability) before q and pagination. Every clause carries information, though the semicolon-chained phrasing is packed tightly enough to slow parsing slightly.

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 must describe return values and it does: price, per-tool input schema, title ordering, and page.next for continuation. Auth, cost, and pagination are all covered, so nothing needed to call it correctly is missing.

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?

Schema description coverage is 100%, so q and cursor are already documented, establishing a baseline of 3. The description only marginally extends this by tying cursor to 'page.next' and clarifying that q matches id, title, or description; it adds no format or edge-case detail beyond the schema.

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?

The description names a specific verb and resource ('Tools callable through POST /v1/tools/{id}') and elaborates the returned payload: price in USDF base units, each tool's input schema, and ordering by title. An agent can distinguish this catalogue lister from siblings like list_models, agents_market_search, or quote_tool without opening any schema.

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?

It gives real invocation context ('No key needed', 'every tool listed can be called now') and explains what q narrows, but never states when to choose this over agents_market_search or quote_tool, nor any exclusion. Usage is implied by the 'callable now' framing rather than stated as guidance.

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