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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds real context beyond them: the accepted input universe is restricted to Postey-owned links, and the tool returns metadata only, not post text. The trailing 'Read-only' mostly restates the annotation, which keeps this from 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 dense sentences, front-loaded with what it does and immediately followed by the 'only lookup' scoping rule and the accepted-input restriction. No filler, though 'Read-only' duplicates the annotation and could be dropped without loss.

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 single-parameter lookup with an output schema present, the description covers everything an agent needs: accepted input forms, what comes back, what does not come back, and the out-of-scope URL types. No further explanation of return values is required since the output schema defines them.

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?

Top-level schema coverage is 0% (the wrapper 'request' object is undocumented), so the description has to carry weight, and it does: it names the accepted forms (app.postey.ai/?d=..., share URL, raw share_id). That said, the nested share_link field already enumerates the same accepted formats, so the added meaning is mostly the extra URL example and the negative constraint on non-Postey URLs.

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 (Resolve) and a specific resource (Postey share URL or share_id), and names the exact output shape (post_id, account, platform, status). It distinguishes itself from content-fetching siblings by declaring 'Metadata only' and pointing at the content path instead.

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?

Gives strong context: 'the only lookup available when a share link is all there is', plus an explicit negative boundary (not Instagram, YouTube, TikTok, X or other social URLs) that prevents a whole class of misuse. The alternative for the actual text is described only as a URI pattern rather than by the sibling tool name (e.g. get_post_content), so the routing is one inference short of fully explicit.

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