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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true and destructiveHint=false, so 'Read-only' merely repeats structured data. The description adds nothing about what the estimate represents (reach vs. impressions), whether it costs quota, or how fresh/stochastic the result is — meaningful gaps given openWorldHint implies external data.

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?

Two short sentences, front-loaded and free of padding. However, the second sentence duplicates the annotations, so it does not earn its place.

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?

With no output schema, the description should explain what an 'estimated audience' returns — a count, a range, a demographic breakdown, a confidence interval. It supplies none of that, and the undocumented 'extra' parameter is left unexplained, so an agent cannot call this confidently.

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 0%, so the description must carry parameter meaning, and it does not. account_id (uuid) is at least inferable as the organization identifier, but the nested 'extra' object with additionalProperties is entirely opaque in both schema and description.

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 is a noun-phrase restatement of the name and title ('Estimate post audience' → 'Estimated audience for an organization post') and never states a verb or the action being performed. It adds only the word 'organization' as scope, which does not distinguish it from siblings like get_post or list_post_reactions.

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?

There is no when-to-use guidance, no prerequisites, and no mention of alternatives. 'Read-only' describes safety, not usage context, so an agent gets no help deciding when to call this rather than get_post.

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