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

The description goes beyond annotations by detailing error behavior: 'on invalid, missing, or malformed input this tool never raises a protocol error — it returns {"error": ...}' and that it always returns a requested error. It confirms read-only and idempotent behavior beyond the annotations, and explains what results look like. No contradiction with annotations exists.

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 highly concise with 3 short paragraphs, each earning its place. It front-loads the purpose in the first sentence, then delivers a clear example, usage guidance, error handling, and safety guarantees—all in fewer than 100 words. No fluff or repetition.

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 the tool's complexity (single parameter, good annotations, provided output schema), the description is complete. It covers purpose, usage, behavior, error handling, and safety. The descriptions and sister names provide clear differentiation from siblings. There is no missing information for an agent to 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 adds value by showing a typical input format with an example and specifying that the text needs at least 3 sentences, which is not fully captured by the schema's description. This additional context justifies a 4, though no detailed parameter metadata is added.

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 clearly states the tool's purpose with a specific verb-resource combination: 'Map a draft's sentence rhythm and find where it goes flat.' It immediately distinguishes itself from sibling tools like 'ai_tell_scan' by explicitly naming it as an alternative for a different use case. The example output further solidifies understanding.

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 provides explicit guidance: 'Use when prose reads flat and sentence-length pattern is the suspect. Not for a full inventory of tells (ai_tell_scan).' This tells the agent exactly when to use this tool and when to choose a sibling instead. The retry safety note after error also clarifies correct usage patterns.

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