Stream

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

With no annotations provided, the description carries full burden for behavioral disclosure. It states this is an update operation (implying mutation) and clarifies partial update behavior, but lacks critical details like permission requirements, error handling, or rate limits. For a mutation tool with 10 parameters, this is insufficient transparency.

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 extremely concise with two clear sentences. The first states the core purpose, and the second adds crucial behavioral context about partial updates. Every word earns its place with zero redundancy, making it efficiently front-loaded and well-structured.

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 complexity (10 parameters, mutation operation, no annotations) and the presence of an output schema, the description is incomplete. It doesn't explain parameter meanings, usage context, or behavioral implications beyond partial updates. For a customer update tool with many sibling operations, more guidance is needed despite the output schema.

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 description coverage is 0%, so the description must compensate for undocumented parameters. It only mentions 'fields' generically without explaining what fields are available, their purposes, or constraints. With 10 parameters (9 optional), this leaves significant semantic gaps, failing to add meaningful value beyond the bare 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's purpose: 'Update fields on an existing customer.' It specifies the verb ('update'), resource ('customer'), and scope ('existing'), distinguishing it from create_customer. However, it doesn't explicitly differentiate from update_product or other update operations, keeping it at 4 rather than 5.

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 provides no guidance on when to use this tool versus alternatives like get_customer or delete_customer. It mentions partial updates ('Only the fields you provide will be changed'), which is useful but doesn't address sibling tools or contextual usage scenarios, resulting in minimal guidance.

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