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

Annotations already flag destructiveHint=true, so the bar is lower, yet the description adds real value: it marks this as a WRITE, clarifies that nothing is permanently lost because the CDN refetches from origin, and warns that the origin absorbs the refill load. It stops short of permission or rate-limit details.

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?

Front-loaded 'WRITE.' marker, then the effect, then the trade-off, then the API endpoint — 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?

For a two-parameter mutation with no output schema and annotations covering destructiveness, the description supplies the missing consequence narrative. Only auth/prerequisite context is absent, which is a minor gap.

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 both parameters are already documented, and cache_tag's meaning is repeated rather than extended. Baseline 3 is appropriate given the schema does the heavy lifting.

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 the cached content of one pull zone') with explicit scope ('everything, or only files carrying a cache tag'). This differentiates it from the sibling bunny_purge_url, which operates on a URL rather than a whole zone.

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 explains the two purge modes and their trade-off, which implies when each is appropriate, but it never names the alternative tool (bunny_purge_url) or states when not to purge a whole zone. Usage is inferable but not spelled out.

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