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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds genuinely new behavior: the tool is free, it consumes caller-supplied data only, and that evidence is never independently verified — an important trust caveat an agent would otherwise miss.

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 short clauses, front-loaded with the cost signal and the core verb, with no filler. It could be slightly tighter, but every sentence carries information.

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 single-parameter, read-only comparison tool this covers what is compared and the data-trust caveat. With no output schema, the description never indicates what the comparison returns (deltas, pass/fail, a verdict), which leaves a real gap for an agent deciding whether to call it.

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 metric list in the description maps onto the schema's metric enum, and 'dated' and 'caller-supplied' gesture at observed_at and source, so some meaning is added. However, the before/after ordering, the requirement that both points share a metric/unit/asset, and the value format are left to the schema, which has no description on the top-level request param.

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 gives a specific verb (compare) plus the resource family it operates on (dated asks, sales, bids, pools, funding, liquidity, holders) and adds a distinguishing constraint ('without mixing metrics'). No sibling tool in the list does market-evidence comparison, so an agent can place 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?

Implied usage is clear enough: compare two dated evidence points for the same metric. 'Free' gives a cost signal and 'without mixing metrics' implies a selection constraint, but there is no explicit when-to-use/when-not guidance or named alternative.

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