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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive. The description adds valuable behavioral details: it verifies the raw workbook SHA-256 before returning source-header row values, and states that it proves the number with no re-query. This goes beyond the annotations without contradicting them.

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 about 80 words and front-loaded with the core purpose. Each subsequent sentence adds necessary context: input shapes, verification behavior, and use case. No redundant 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?

Despite minimal schema, the description covers the purpose, input requirements, and behavioral outcome (verified source-row values). An output schema exists, so the description need not enumerate return fields. It is complete for an agent to select and invoke 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?

The input schema is nearly empty (params is an arbitrary object/null, 0% coverage). The description fully compensates by specifying exactly what to pass: a citation object from either citations[ref].verify or a detail record's citation from include_records. This is critical semantic information not present in 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 first sentence clearly states the action and target: 'Fetch and hash-verify the raw source row behind a returned citation.' It uses a specific verb and resource, and distinguishes from sibling query/describe tools by focusing on evidence retrieval for a citation.

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 description explicitly says when to use it: 'Use this when an agent must prove an answer from the underlying source row.' It also explains the two input shapes from query tools, providing clear context. It doesn't explicitly list alternatives or exclusions, but the use case is unambiguous.

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