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

Annotations already declare readOnlyHint and idempotentHint, so safety is covered. The description adds value by detailing the return payload (IDs, methods, paths, summaries, deprecation status) and the comprehensive nature of the result. It doesn't mention potential pagination or error cases, but for a list-all tool this is reasonably transparent.

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-structured with clear sections (Purpose, When to use, Parameters, Returns). Every sentence adds useful information, and it is front-loaded with a concise summary. No filler content.

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 that this is a simple one-parameter tool with annotations and no output schema, the description covers all necessary context: purpose, usage criteria, parameter format, and return value. It is fully complete for an agent to select and invoke it 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?

Schema coverage is 100%, but the schema's description is terse ('required,'). The tool description adds important semantic detail by specifying that specId is a 32-character MD5 hash ID, which helps the agent understand the expected format. This goes beyond the schema baseline.

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 uses a specific verb ('Lists') with a clear resource ('all endpoints across an entire API specification') and explicitly distinguishes itself from sibling tools by noting its comprehensive scope. The phrase 'spanning all collections and tags' plus the contrast with `endpoint_by_collection` and `endpoint_by_tag` makes the purpose unmistakable.

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 description has a dedicated 'When to use' section that lists concrete scenarios (e.g., 'show me all endpoints in API X') and explicitly names alternative tools for narrower scopes. This provides clear guidance on when to choose this tool over siblings.

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