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

Beyond the annotations (readOnly=false, destructive=false), the description adds that generation costs 100 credits per photo, requires a connected Photo AI Studio account, and starts the sign-in flow. These are meaningful behavioral and side-effect disclosures. It does not cover rate limits or async result handling, though wait_for_result is described in the schema.

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?

Three tight sentences front-load the purpose, then provide workflow prerequisites, then the account requirement. No redundant or filler content; every sentence adds needed context.

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 a 9-parameter tool with no output schema, the description communicates the two modes, prerequisites, cost, and auth flow. Conditional requirements and the prediction_id/async pattern are left to parameter descriptions, which document them, so the overall tool definition is reasonably complete but not exhaustively summarized up front.

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%, so the parameter baseline is 3. The description adds workflow relationships (images come from upload_image; theme slugs come from browse_themes) but does not add detailed semantics for individual parameters beyond what the schema already states.

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 uses a specific verb and resource: 'Generate AI photos from face images,' and distinguishes the two generation modes ('preset theme or custom prompt'). It also references sibling tools by workflow ('upload_image first,' 'browse_themes'), which separates this generation step from upload, theme browsing, editing, and video creation.

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?

It gives explicit usage prerequisites: upload face photos with upload_image first and find theme slugs with browse_themes. It also discloses the account/sign-in requirement. It does not explicitly state when-not-to-use vs edit_image or create_video, so it misses full exclusion guidance.

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