analyze_image

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

Discloses limitations (does not decode image, no pixel dimensions) and rate limiting, adding value beyond readOnlyHint and openWorldHint annotations. 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?

Five sentences covering all essentials: what it does, prerequisites, limitations, usage preference, and rate limiting. No unnecessary words.

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 output_schema exists (so return values need no explanation), annotations provide safety context, and schema covers all parameters, the description is complete: it tells what to do, prerequisites, limitations, and alternatives.

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%, baseline 3. The description adds context by explaining the blob parameter as a result from upload_image and the includeOptimizationSuggestions parameter's default behavior, but parameter details are already well-covered by 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 description clearly states the tool analyzes image blob metadata (MIME type, size, derived format, optimization thresholds) and optionally returns suggestions. It explicitly distinguishes from siblings by noting it does not decode the image and cannot report pixel dimensions, and differentiates from upload_image for pre-flight checks.

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?

Provides explicit guidance: use upload_image first, then pass the blob reference; prefer this tool over upload_image for pre-flight size checks; notes no authentication required and rate limiting.

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