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

Annotations already indicate read-only and open-world, but the description adds valuable behavioral disclosure: provenance.sourceAuthority identifies the live EPREL API vs synthetic fixtures, 'supplier-declared data only' and 'Jithox verifies nothing' warn about data trust, and the failure mode 'incompatible_comparison' is documented. No contradictions 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?

The description is front-loaded with the core purpose in the first sentence. Every subsequent sentence adds a distinct caveat (compatibility, failures, provenance, data trust), making it dense but not redundant. It earns each sentence without being verbose.

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 that an output schema exists, the description need not explain return values. It covers constraints (compatible records, common metrics), failure modes, data source provenance, and limitations (no verification). This is complete for a read-only comparison tool with rich annotations and schema.

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?

Both parameters are fully described in the schema (100% coverage), so the baseline is 3. The description references compatibility and common metrics, which relate to parameter usage, but does not add syntax or format details beyond the schema. It does not meaningfully enhance parameter understanding.

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-resource pair ('Compare two or more COMPATIBLE records on their COMMON supplier-declared metrics') and clearly limits the tool to a value table only, distinguishing it from ranking or advice tools. It also explicitly scopes to common metrics and excludes cross-group comparisons, making the purpose unambiguous.

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?

Clear context is provided: the tool is for comparing compatible records on common metrics, and cross-group comparisons fail safely with 'incompatible_comparison'. It explicitly excludes ranking and buying advice, giving when-not-to-use guidance. However, it does not name alternative sibling tools directly, so it stops short of explicit alternative routing.

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