users_identify

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

No annotations are provided, so the description carries the full behavioral burden. It discloses the core side effect ('merges the alias profile into the identified user'), which is valuable, but it omits reversibility, permission requirements, rate limits, and what happens to the alias profile after merge.

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 two sentences with no wasted words, and the key operation is front-loaded before the merge effect. It is appropriately sized for a tool with a fully documented schema.

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?

The description covers the purpose and the merge behavior, and the schema is fully documented. However, for a mutation tool with no annotations and no output schema, it lacks important context such as irreversibility, authentication needs, and explicit sibling differentiation.

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 100%, so the schema already documents all parameters. The description mentions 'external_id' but adds no syntax, format, or constraint details beyond what the schema provides, matching the baseline score for fully covered schemas.

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 states a specific verb (Identify) and resource (alias-only user profile) and explains the merge effect. It distinguishes this from sibling tools like users_alias_new or users_alias_update by targeting alias-only profiles, but it does not explicitly name an alternative for comparison.

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 phrase 'alias-only user profile with an external_id' implies the condition for use, but there is no explicit when-to-use versus alternatives like users_merge or users_alias_new, and no mention of prerequisites or exclusions.

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