Authenticate a user (password)

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

No annotations are provided, so the description carries the burden of behavioral disclosure. It adequately covers return value (auth token and user record) and an important side-effect trait (does not affect the MCP's own superuser session). It does not disclose error behavior or rate-limit implications, but for an authentication operation this is reasonable and not misleading.

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 three crisp sentences: the first states the action and inputs, the second states the return and side-effect, the third states the use case. It is front-loaded, avoids filler, and every sentence contributes meaningfully to selection and invocation.

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 moderate-complexity auth tool with no output schema, the description is complete enough: it identifies the required inputs, what is returned, the intended use, and a key behavioral nuance. The schema handles parameter details. It could add explicit comparison with OTP auth, but that is a refinement rather than a necessity.

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?

All four parameters are already documented in the schema with 100% coverage, so the baseline is 3. The description only repeats identity/password at a high level and adds no parameter-specific detail beyond the schema. No extra credit is warranted.

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 uses a specific verb ('Authenticate') with a clear resource ('end user against an auth collection') and explicit credentials ('identity (email/username) and password'). It also distinguishes itself from superuser-related tools by noting it does not affect the MCP's own superuser session, making it distinct among the many auth-related siblings.

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 explicitly states when to use the tool: 'to obtain a token to act on behalf of a user or to verify credentials.' It provides clear context, though it does not explicitly mention alternatives like auth_with_otp or state when not to use it. This is a minor gap rather than a critical one.

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