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

Annotations already declare readOnly, idempotent, non-destructive, so safety is covered. The description adds non-obvious behavior: cards missing from the live feed are served from the archive with expired=true, a semantic the agent would otherwise misread as a live signal, plus the api:read auth requirement.

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 tight sentences, front-loaded with what the card contains, followed by the archive caveat and id provenance. The payload list is dense but each item is informative, with little waste.

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 burden of describing return contents, and it does so richly (evidence trail, invalidation conditions, optional model read, mentions, price history, market stats). An agent knows what it will get and how to interpret the expired flag.

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% and the schema already documents the pattern and an example for opportunity_id. The description only restates the provenance (from get_opportunities) and format (mo_ + 32 hex), adding marginal value over the structured field.

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 and then enumerates exactly what the card contains (evidence trail with source/observed_at, invalidation conditions, model read, mentions, price history, market stats). This is clearly distinguishable from the sibling get_opportunities, which supplies the ids, and from get_opportunity_news.

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?

Explicitly routes the caller to get_opportunities for the opportunity_id and warns to treat archived (expired=true) cards as historical rather than a current signal. It gives context but does not explicitly compare against alternatives like get_opportunity_news or evaluate_opportunity for related needs.

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