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

With no annotations and no output schema, the description carries the full burden, and it does disclose useful result behavior: every result carries source_url, verified_at, and a recency delta so the caller can apply a freshness tolerance. It omits pagination, result limits, and any rate/auth behavior, so it is not fully complete, but it adds real behavioral value.

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 sentences, front-loaded with the core purpose and then the freshness metadata. No filler, no repetition of the schema, and the most decision-relevant fact (results are verifiable and time-stamped) comes second.

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 discovery tool with no annotations and no output schema, the description covers purpose and result shape adequately. It would be fully complete with a note on result volume/pagination or how it relates to get_offer, but the freshness disclosure covers the main risk an agent faces here.

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 provider, capability, and agent_usable_only, including the default. The description adds no parameter-level meaning beyond that, which is the baseline expectation when the schema does the work.

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 names a specific verb and resource ('find free tiers, trial credits and discounts on AI APIs'), so the agent knows exactly what the tool returns. It doesn't differentiate itself from the sibling get_offer, which is the only gap keeping it from 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?

Usage is implied ('an agent can use') but there is no explicit when-to-use, when-not-to-use, or comparison against the siblings check_api_health and get_offer. The agent must infer that this is the discovery tool and get_offer is the detail tool.

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