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

With no annotations, the description carries the full burden and delivers real behavioral facts: repost_count and reactions-by-kind are null because the source gives totals only, the call costs 3 credits whether cached or not, and failed calls are refunded. It stops short of stating auth/permission requirements or error semantics, so it is strong but not exhaustive.

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?

Four tightly packed sentences, front-loaded with the purpose, then return fields, the null caveat, sibling routing, and pricing. Every sentence carries a distinct fact with no filler.

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-fetch tool with no output schema and no annotations, the description compensates by enumerating returned fields, flagging the null fields, disclosing cost/refund, and routing comments/reactions elsewhere. Nothing an agent needs to invoke it correctly is missing.

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 description coverage is 100%, so both url and fresh are already well documented, and fresh's cache/trial behavior is spelled out in the schema. The description's 'cached or not' cost note adds only a sliver beyond the schema, so the baseline of 3 is appropriate.

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?

Starts with a specific verb+resource+scope: 'Fetch one post by its URL.' It also enumerates the exact fields returned (text, images, author, published_at, reaction_count, comment_count), which lets an agent distinguish it from listing tools like get_linkedin_posts without opening schemas.

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?

Routes the agent to alternatives explicitly: 'Use linkedin/comments for its comments and linkedin/reactions for who reacted' (matching the get_linkedin_post_comments/get_linkedin_post_reactions siblings). This is clear usage context, but there is no explicit 'when not to use' or note on scope limits beyond the comment/reaction handoff.

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