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

Annotations already establish the read-only, non-destructive nature, and the description adds meaningful behavioral detail by noting that X-API-Key is only an alias and that the tool does not echo the secret. This goes beyond the annotation coverage without contradicting it.

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 short sentences front-load the core purpose and immediately add the alias and security caveat. No filler or repeated schema 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?

For a zero-parameter, read-only verification tool, the description covers purpose, authentication header options, and the non-echo behavior. It does not state the response/return semantics, but the endpoint and verb make the validity outcome fairly inferable.

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?

With zero parameters and 100% schema coverage, there is no parameter documentation gap. The description adds value by specifying where the key is sourced (header rather than JSON body), which is useful given the empty schema.

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 operation as confirming the caller key via FEED_DIGEST_API_KEY or Authorization: Bearer, with the endpoint GET /keys/verify. The verb-resource pair is specific, though it does not explicitly contrast with sibling key-management tools or explain why the title also lists rss digest/atom feed/feed items.

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 practical context: use this to confirm a caller key and present it via one of the named header forms. It does not explicitly say when to prefer this over issue_key/revoke_key/rotate_key or state when not to use it.

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