createUserPhoto

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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false. Description adds 'Writes live data.' and crucial precondition about file existence. No contradictions; additional context beyond 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?

Seven well-structured sentences with headers. Each sentence adds value: purpose, use case, prerequisites, parameter descriptions, cross-reference. No redundancy or fluff.

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?

For a 3-param tool with no output schema, description covers all needed aspects: purpose, usage context, parameter meanings, preconditions (file must exist), and related tool. Complete for agent invocation.

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 only 33% (file description). Description explains all three parameters with added semantics: user_id as 'the member', type as 'slot: logo, photo, or cover_photo', file as 'image filename (must already exist in site storage)'. Greatly compensates for schema gaps.

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?

Description clearly states 'Create a new userphoto record. Writes live data.' It distinguishes from sibling updateUserPhoto (mentioned in 'See also') and other create tools by specifying 'user photo' resource. Specific verb+resource with clear scope.

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?

Explicitly says 'Use when: attaching a new photo record to a member.' Provides precondition (file must exist in site storage) and mentions alternative updateUserPhoto for modifications. No exclusion criteria but context is sufficient.

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