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

Annotations already cover read-only, idempotent, and non-destructive behavior. The description adds value by stating that a missing row is never converted to zero, listing the return contents, and clarifying that balances are not daily flows, wrongdoing evidence, or investment advice. No contradiction with annotations.

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 sentences with no fluff: purpose and source, return contents and missing-row behavior, then usage examples and a disclaimer. The key purpose is front-loaded, and every sentence earns its place.

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 tool with three parameters, no output schema, and annotations covering safety, the description is quite complete: it states purpose, return fields, missing-row handling, and interpretation caveats. It could mention error handling or what happens with invalid symbols, but overall it provides enough context for correct invocation.

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%, providing a baseline of 3. The description adds the 'two to eight' constraint on symbols, clarifies that settlement_date must be a single date within the hot window, and gives examples that use the parameters. This adds meaning beyond the schema.

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 clearly states the tool compares two to eight ticker symbols on a single SEC fails-to-deliver settlement date from a self-hosted snapshot, and lists what it returns. It distinguishes from sibling tools by the 'compare' verb and the same-date constraint, and provides concrete usage examples.

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?

It gives explicit usage examples ('compare GME, AMC, and TSLA FTD balances' or 'which selected symbol had the largest published balance on 2026-08-14?') and cautions that point-in-time balances are not daily flows. However, it does not explicitly name alternative tools or state when not to use this tool, so no exclusions are provided.

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