update_profile

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

The description adds important context beyond the annotations: 'unspecified fields are preserved from the existing profile' clarifies partial update semantics. Annotations already provide destructiveHint, idempotentHint, and openWorldHint, but the description adds the preservation behavior and authentication note.

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 concise, with four sentences that each add necessary information (purpose, behavior, prerequisite, auth/rate limits). It is front-loaded with the core update action, and every sentence earns its place.

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 the presence of an output schema (not shown), the description does not need to cover return values. It comprehensively covers purpose, parameters, behavior, prerequisites, authentication, and rate limiting. The sibling tools list includes get_user_profile and upload_image, which are appropriately referenced.

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 has 100% description coverage with detailed parameter descriptions. The description adds value by explaining that omitting a parameter leaves it unchanged, and by stating the prerequisite of using upload_image for avatar/banner blobs. This exceeds the baseline of 3.

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 'Update user profile on AT Protocol' and enumerates the specific fields that can be modified (display name, description, avatar, banner). This provides a specific verb and resource, and implicitly distinguishes from the sibling get_user_profile tool which is read-only.

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 explicit prerequisites: 'Use upload_image to prepare blob values for avatar or banner before calling this tool.' It also notes authentication requirements and rate limiting. While it does not explicitly state when not to use, the context implies it is for authenticated profile updates, and alternatives like get_user_profile exist for reading.

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