Metrics for one post

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

Annotations already cover safety and side effects (readOnlyHint=true, destructiveHint=false, idempotentHint=true), so the bar for added behavioral value is lower. The description adds a non-obvious metric nuance: 'Reply metrics count direct replies only, not the whole tree underneath.' This is genuinely useful behavioral context beyond annotations. It doesn't discuss error cases or output shape, but annotations cover the safety profile.

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, both substantive. The first sentence names the exact metrics and scope; the second adds an important definitional caveat. Every word earns its place, and the most important information is front-loaded.

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 read-only metrics tool with robust annotations and a fully described schema, the description is mostly complete: it names all returned metric categories and flags an important counting nuance. There is no output schema, so a bit more detail about return shapes or time ranges would be nice, but the description provides enough for an agent to select and invoke the tool correctly.

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 the schema already documents the id and account parameters adequately. The description adds no additional parameter-level detail beyond the overall scope of 'one of your posts.' Baseline 3 is appropriate because the schema carries the burden.

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 clearly identifies the tool as returning metrics—views, likes, replies, reposts, quotes, and shares—for a single post. It conveys the resource and scope, and the metric enumeration makes it easy to distinguish from account-level tools like get_account_insights. However, it doesn't explicitly differentiate itself from get_post or get_posts, so it stops short of full sibling differentiation.

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?

Usage is implied: it is the tool to call when you need engagement metrics for one of your own posts. But there is no explicit guidance on when to choose it over get_post, get_account_insights, or get_replies, and no mention of alternatives. A clear context is present, but exclusions and alternatives are not.

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