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

Annotations only supply destructiveHint=true, so the description carries real weight and delivers: trailing-slash purges everything beneath the path unless exact_path is true, wildcards are accepted, and the CDN refetches from origin. It stops short of stating irreversibility, propagation delay, or rate limits, keeping it below a 5.

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?

Three tight sentences, front-loaded with the write classification and the core action, then the scoping edge cases, then the API mapping. No filler or redundancy.

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?

For a 3-parameter mutation with no output schema and full schema coverage, the description covers behavior, edge cases, and the upstream endpoint. Only the absence of any statement about propagation or permanence of the purge keeps it from being fully complete.

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 already 100%, so the baseline is 3, but the description adds genuine nuance by explaining the interaction between a trailing '/' and exact_path, plus wildcard support -- semantics the schema alone does not spell out.

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 ('Purge one URL from the CDN cache') plus a scoping restriction ('one URL'), which cleanly separates it from the zone-wide sibling bunny_purge_pull_zone_cache. The leading 'WRITE' label signals the operation class immediately.

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 word 'one URL' implies this is the single-URL purger rather than the zone-wide purge, but the alternative (bunny_purge_pull_zone_cache) is never named and no explicit when-to-use/when-not guidance is given. Usage is inferable from scope but not stated.

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