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

Annotations already establish that this is a read-only, idempotent, non-destructive call, so the safety bar is met by structured data. The description adds genuine context beyond that: fills are public on-chain at settlement, and it enumerates the returned fields including fee and the Bookrunner's share. It omits pagination, ordering, and result-size behavior, which keeps it from 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?

A single sentence with the resource and scope front-loaded, followed by the returned field list. The field enumeration is dense but earns its place given there is no output schema. No filler or repetition.

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 one-parameter read tool with no output schema, the description covers scope, provenance of the data, and the shape of the return, which is solid. It falls short on ordering, limits, and how the result differs from the tape or trades endpoints, which an agent would need to pick correctly.

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?

There is a single required parameter with 100% schema description coverage, including the note that transactions are built for that address to sign. The description only echoes that the fills belong to a wallet, adding no format or constraint detail beyond the schema. Baseline 3 is appropriate 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 states a specific resource and scope: a wallet's Zero Dark fills, enumerated by field. An agent can tell it returns executed fills rather than open orders. It does not, however, distinguish itself from close siblings like darkroom_tape or trades, so differentiation is left implicit.

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?

There is no when-to-use guidance and no named alternative, despite the presence of darkroom_orders, darkroom_tape, and trades in the sibling set. The phrase 'all public on chain at settlement' is descriptive context about the data, not a routing condition. The agent must infer from the name alone when this is the right call.

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