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

Annotations already cover safety (readOnlyHint=true, destructiveHint=false, openWorldHint=true), yet the description adds non-trivial context beyond them: it performs NO platform action, returns guidance text only, costs no credits, needs only authentication, and phrases answers as concrete '<tool> action=…' calls rather than guessed endpoints.

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?

Dense but front-loaded: the core purpose leads, then boundaries, then sibling differentiation, then cost/auth notes. Slightly heavy with parentheticals and repeated emphasis on the no-action guarantee, but every sentence carries actionable information.

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 still tells the agent what comes back (grounded answer or clarifying question) and what does not (no actions, no side effects). Combined with full schema coverage and rich annotations, an agent has everything needed 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%, so the baseline is 3; the description still adds value by explaining that action='describe' yields the full action/param reference and that a vague question yields a clarifying question instead of an answer, which shapes how the agent should phrase input.

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: a natural-language 'how do I…' question about Fastio returns a grounded, product-aware answer (or clarifying question) in one call. It explicitly distinguishes itself from the closest sibling by declaring 'Q&A over the user's uploaded files (RAG) is the ai_manage tool; how-to answers questions about Fastio ITSELF.'

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 explicit when-to-use (questions about Fastio itself), when-not (RAG over uploaded files goes to ai_manage), the precondition (authenticated user, no org needed), the cost profile (no credits), and the operational boundary (explain-only, no platform actions). Nothing is left to inference.

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