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

Annotations already declare readOnly, idempotent, closed-world, non-destructive, so the safety profile is covered. The description adds genuinely non-obvious traits: the data is yesterday's snapshot, "Dead coins count" (survivorship handling), a fixed three-hour horizon, and that the tool is free while base_rate is paid. It still doesn't describe pagination or output shape, but it discloses the behavioral quirks that matter most.

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?

Front-loaded with cost and scope, and every clause (bands, metrics, horizon, dead coins, paid alternative) carries information. The "For:" sentence is a fragment and the first sentence is long, but no wording is redundant.

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: per-band counts, breakout shares at four thresholds, and median peak are all specified. Cost, data freshness, and horizon are covered; only result ordering/volume is unstated.

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?

The tool takes no parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The band range ($5k-10k up to $250k-1M) clarifies the population being aggregated even though it isn't a callable argument.

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?

Names a specific resource (yesterday's pump.fun odds by market-cap band) and the exact metrics returned: coins first traded per band, share reaching 2x/5x/10x/20x within three hours, and median peak. It also distinguishes itself from check_coin (per-coin odds) and base_rate (any window), so an agent can route without opening a 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 "For:" clause gives concrete triggering questions ("odds a pump.fun coin at $20k does a 2x") and it explicitly redirects to check_coin when the question is about a specific coin's deployer/early buyers, and to base_rate for arbitrary windows. When-to-use and alternatives are both stated.

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