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

Annotations declare a non-destructive write operation, and the description adds substantial context beyond that: it scores up to 10 recent notes, resolves the target publication in a specific default order, enforces a 6-hour rate limit, returns the saved benchmark unchanged with 'rateLimited: true' when throttled, and explicitly states 'Never publishes.' This goes well beyond the annotation hints.

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?

Six compact sentences, each delivering essential information: purpose, scoring scope, default resolution, account restriction, rate limit behavior, and safety guarantee. The purpose is front-loaded and no sentence is wasted.

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 an output schema present, return values need no explanation. The description covers mutation behavior, rate limiting, default target resolution, account constraints, and explicit safety (never publishes), which is complete 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 description coverage is 100%, so the single parameter is already well defined. The description adds value by clarifying the default resolution order – 'the publication of the saved benchmark, then the default connected Substack publication' – which the schema only refers to vaguely as 'the default publication.'

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 states a specific verb ('Recompute') and resource ('Substack Notes benchmark'), plus the save action and scoring scope. No sibling tool performs benchmarking, so it is clearly distinguished from the surrounding automation tools.

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 provides clear operating context: personal account only, limited to once every 6 hours, and the fallback when rate limited. However, it does not explicitly say when to use this tool versus alternatives, though no alternative benchmark tool exists.

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