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

Beyond the readOnly/idempotent annotations, the description discloses significant behavioral nuances: the report is 'limited' and 'not a certificate of authenticity', absence of a mark is not evidence of camera capture, and the C2PA field only reports container presence without parsing or validation. It also advises careful reading and repetition of summary lines. This richly informs the agent about the tool's limitations and correct interpretation.

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: it opens with a clear purpose, adds a scope constraint, then presents crucial caveats in bold for emphasis, and ends with a usage tip. Every sentence contributes essential information—no fluff. It is appropriately sized for the complexity of the 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?

Without an output schema, the description does a strong job conveying what the tool reports (watermark, IPTC, C2PA presence) and how to interpret it. It mentions 'summary lines' implying a structured output, but does not enumerate the exact fields. For a read-only inspection tool, this is nearly complete; a small gap remains regarding the precise return structure.

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 fully describes image_base64 (base64 JPEG/PNG, up to 8MB, data URL accepted) with 100% coverage. The description adds no additional parameter-specific details, but the schema alone is sufficient. As per the calibration baseline for high schema coverage, a 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 states a specific verb ('Inspect') and resource ('an image'), and enumerates three concrete provenance signals (Duskly watermark, IPTC digital source type, C2PA container presence). It also clarifies the tool operates on images Duskly did not produce, which distinguishes it from related generation tools. This makes the purpose unambiguous and easily differentiable from sibling tools.

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 gives a usage constraint ('Works on images Duskly did not produce') but does not explicitly contrast with sibling tools or state when to choose this over alternatives. It implies the tool is for verification, not classification or generation, but lacks explicit exclusions or references to alternatives. This is adequate but not fully explicit.

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