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

Annotations declare readOnlyHint=true, and the description adds substantial behavioral context: the weighting formula, sources, daily update frequency, and how stale data can pause downstream jobs. It also notes the Gold tier requirement for history via the schema description. 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?

The description is well-structured: first sentence defines the output and formula, second sentence provides usage context, and third sentence states update frequency. Every sentence adds value with no redundancy.

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 the absence of an output schema, the description lists the concrete output fields (quality_index, freshness_hours, completeness_pct, stability_score) and explains the computation and sources. It also covers update frequency and usage context, making it complete for this tool's complexity.

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 schema description for the only parameter 'days' is comprehensive (100% coverage), including the optional history behavior and Gold tier constraint. The tool description itself does not add parameter-specific meaning, so the baseline of 3 is appropriate.

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 returns a 0-100 source quality and freshness index with an explicit formula and data sources. It distinguishes this tool from siblings by specifying the exact purpose, output fields, and the computed metric.

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 provides explicit 'Call when' guidance for user questions about freshness, staleness, completeness, or source reliability, and for downstream pipeline refresh timing. It does not mention alternatives or when-not-to-use, but the context is clear enough.

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