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

Annotations already mark readOnlyHint=true; the description adds meaningful behavior beyond that: required Authorization Bearer token, 'Descriptive, not a recommendation', daily free allowances, and overage pricing via x402/USDC. This gives the agent useful expectations about auth and cost without contradicting the read-only hint.

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?

The description is a single dense sentence that leads with the core purpose, then covers auth, semantics, and quotas. The pricing detail is somewhat long but relevant and not wasteful. It earns 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 points to get_smart_list_metrics to imply the return shape and adds headlines. It also covers auth, quota, cost, and non-recommendation semantics. It could be more explicit about pagination response shape, but the reference to a sibling plus the parameter schema covers most needs.

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 input schema already documents limit, offset, and news_days thoroughly. The description adds no parameter-level detail beyond hinting at headlines, which is acceptable given the schema handles semantics.

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?

Clearly identifies the operation: retrieving per-symbol metrics plus headlines for the caller's own watchlist. Differentiates from the sibling get_smart_list_metrics by scope ('your own watchlist') and by the added headlines, so an agent can distinguish it 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?

The description anchors usage by comparing to get_smart_list_metrics and adds the distinguishing 'plus the latest headlines, for your own watchlist'. It does not explicitly state when NOT to use it, but the comparison makes the intended context clear enough.

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