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

Annotations declare it is a non-read-only, idempotent, open-world mutation, and the description adds real context beyond that: it writes a new snapshot, enumerates supported providers, and warns that unsupported providers yield an 'unsupported snapshot'. Auth requirements and rate limits are not covered, but the provider/fallback behavior is genuinely useful disclosure.

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 sentences, front-loaded with the core action, then the provider caveat, then the routing hint. Slightly list-heavy with the provider enumeration, but every sentence carries actionable 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 mutating fetch-and-snapshot tool with no output schema, it covers what the operation does, which providers work, what happens otherwise, and when to prefer it. It does not describe the returned snapshot's shape, which is a minor gap given no output schema exists.

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 postId and window are already documented with the lifetime default. The description adds no syntax or format detail for either parameter, so the schema does the heavy lifting and the baseline 3 applies.

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 chain — fetch fresh analytics from the provider, store a snapshot, return it — and names the resource (published post analytics). It is clearly distinguishable from the sibling get_analytics, which reads stored data.

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?

Explicitly routes the agent: 'Call this before get_analytics when you need current numbers rather than the last stored snapshot.' This gives both the alternative and the condition that selects this tool over it.

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