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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered; the description adds genuinely useful behavioral context beyond that: data is synced on a delay, so recent posts may have no metrics, which prevents an agent from misreading empty results as an error. It does not cover rate limits, pagination behavior, or result ordering, which keeps it below 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 tightly packed sentences, front-loaded with the core action, then the level semantics, then the staleness caveat. No filler, no restatement of the tool name, and each sentence carries decision-relevant 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?

With an output schema present and full schema coverage, the description need not explain return values or filter syntax, and it covers the main conceptual risks (mode confusion, sync delay). The only minor gap is that the optional filters (postId, platform, accountIds) and their interplay with level are never acknowledged in prose.

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 baseline is 3, and the description earns an increment by explaining what the level parameter actually changes in the returned payload (per-post metrics with totals vs. account snapshot plus daily series). It adds little for the remaining filters (postId, platform, accountIds), which are left entirely to the 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?

States a specific verb and resource ("Reads performance analytics") and then splits the tool's two modes with explicit return contents for each: per-post metrics for 'posts' and account snapshots plus daily series for 'accounts'. An agent can distinguish this from siblings like autoposter_get_post or autoposter_list_accounts without opening the schema.

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 clear selection logic between the two levels ('posts' default for per-post metrics with totals, 'accounts' for account snapshots and a daily series when from/to are supplied), so the agent knows which mode to pick. It stops short of naming alternatives or exclusions (e.g. when to use list_posts or get_post instead), so it is clear context rather than full when/when-not guidance.

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