users_lookup_by_email

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

With no annotations, the description must bear the burden of disclosing behavioral traits. However, it only states 'Find a user with an email address' without addressing what happens if the email is not found, case sensitivity, error handling, or response format, which are critical for a lookup tool.

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 (one sentence) and front-loaded, but it lacks necessary context. While brevity is positive, the single sentence does not fully earn its place as it omits important operational details.

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 tool has an output schema and no annotations, the description should provide context about the lookup behavior (e.g., uniqueness, validity checks). It fails to address potential ambiguities, making it incomplete for an AI agent to reliably invoke.

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 0% description coverage for the 'email' parameter, and the description does not add meaningful context beyond restating the parameter's purpose. For a tool with a single required parameter, more detail on format (e.g., full email, case sensitivity) is expected.

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 'Find a user with an email address' clearly states the verb (find) and the resource (user by email). It effectively distinguishes from sibling tools like users_info (which uses user ID) and users_list (which lists all users), making the tool's purpose unambiguous.

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. It does not mention scenarios where users_info or search_modules_people would be more appropriate, nor does it specify prerequisites or context.

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