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

Beyond the annotations, the description explains matching logic, tolerance behavior, summing of multiple lots in one order, output categories, premium licensing, and a non-raising error contract with retry safety. This adds substantial behavioral context for a read-only reconciliation tool.

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?

The description is front-loaded with the core purpose, then efficiently covers premium status, example input, matching rules, usage guidance, errors, and retry safety. Despite its length, every section contributes to correct invocation of a complex reconciliation tool.

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?

Given the rich schema, output schema, and annotations, the description is complete enough for an agent to call the tool correctly. It covers the expected input shape, matching behavior, return categories, error handling, and safe retry after correction.

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 coverage is 100%, so the baseline is 3. The description still adds meaningful semantics by showing a typical input example, clarifying that basis may be blank, and explaining how account, asset, sale date, quantity, and proceeds are used in matching.

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 verb and resource: 'Diff the broker's 1099-DA lines against the computed disposals.' It clearly identifies the reconciliation purpose and names build_lots as the source of disposals, but it does not explicitly contrast itself with relevant siblings such as form_8949_rows or match_transfers.

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 a concrete usage condition: 'Use when the form arrives and the basis column is blank for coins that came from your own wallet.' It also adds a clear exclusion, 'Not a substitute for the broker's statement,' though it does not name a specific alternative sibling tool.

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