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

With no annotations, the description carries the full burden. It discloses the return structure in detail, including operations array, total_operations, and surfaces, and explains filtering behavior. It does not mention potential rate limits or auth, but for a read-only list tool, it provides substantial behavioral context.

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?

The description is well-organized into WHEN TO USE, RETURNS, and EXAMPLE sections. Every section contributes essential information: usage context, return fields, and a concrete invocation. It is appropriately sized without fluff.

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?

Given no output schema and no annotations, the description fully compensates by declaring all return fields, explaining the surface concept, and providing a usage example. It is comprehensive enough for an agent to understand what list_endpoints does and how to invoke it.

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 the baseline is 3. The description adds value by explaining the practical meaning of agent_safe ('side-effect-free endpoints') and giving a concrete example with agent_safe: true, going slightly beyond the schema's terse descriptions.

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 immediately states 'List every registered Trillbirds API operation,' using a specific verb and resource. It clearly distinguishes from the sibling tool describe_endpoint by covering all operations rather than just one.

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?

The 'WHEN TO USE' section explicitly says to use this as a first call in an agent session, to filter with agent_safe, and to narrow by surface. This provides concrete context and contrasts with more specific tools like describe_endpoint, even though it does not name alternatives directly.

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