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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavioral context outside the annotations: a 1-credit cost and a 25 calls/day free-tier ceiling, plus the fixed 13-month lookback window. It does not discuss result ordering edge cases or response shape, keeping it short of a 5.

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 scope and contents, with the cost caveat second. Dense but nearly every clause carries payload (time window, returned fields, upcoming list, credit cost); 'DNA score' is unexplained jargon that assumes prior context.

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 usefully enumerates the data columns returned, and it discloses the time window and cost/rate limit an agent needs to budget calls. The content of 'upcoming IPOs' (fields, horizon) and pagination behavior are left unspecified, which is a minor remaining gap.

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 all three parameters (sort, limit, below_ipo) are already documented with defaults and range. The description's mention of 'return since IPO' and 'DNA score' loosely maps to the sort enum values but adds no formatting, interaction, or default behavior beyond the schema, so the baseline 3 applies.

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 resource and scope: U.S. IPOs from the last 13 months, plus upcoming IPOs, with the fields returned (return since IPO, DNA score, revenue growth, lock-up date). An agent can immediately tell this is a recent-IPO screener, though it never explicitly contrasts itself with siblings like stock_dna or rank_dna.

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 rather than stated: you would call this to review recent or upcoming IPOs. There is no explicit when-to-use/when-not guidance and no named alternative for adjacent tasks, but the scope and cost note make the intended call context reasonably inferable.

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