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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety needs no restating. The description goes further by disclosing result semantics the agent would otherwise have to discover: missing readings stay missing, and reporting statuses are ok/empty/unsupported/failed. It also names the required scope metrics:read, which annotations do not cover.

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 tight sentences, front-loaded with scope, then the param modifier, then result semantics, then auth. No filler, no repetition of the title or annotations.

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 carries the return-value burden and does so by explaining the status vocabulary and how absent readings behave. Combined with the schema's limit bounds and the read-only annotations, an agent has enough to invoke it correctly. Pagination or per-status actionability is not addressed, keeping it out of 5 territory.

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 only 50%: limit is documented in the schema, but channelId is bare. The description compensates by explaining that channelId narrows the result set, which is the missing semantic. It does not add format or syntax detail, but the coverage gap is addressed.

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 states a specific verb and resource: reading recent published posts plus network-reported metrics, scoped to channels the credential can reach. That is materially clearer than the name alone and separates it from list_posts or post_results. It stops short of naming the sibling it should be chosen over, so it is not a 5.

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?

It states the scope precondition ('channels this credential can reach'), the auth requirement ('Requires metrics:read'), and that channelId is optional and narrowing. However, it never says when to pick this over account_overview or post_results, so usage is implied rather than directed.

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