Request phone approval

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

Annotations already declare write semantics (readOnlyHint=false), non-idempotency and non-destructiveness, so the safety profile is covered. The description adds real behavioral context beyond that: approval happens out-of-band in the Thndr mobile app, no email code is involved, and the flow continues at login_complete. It doesn't mention request expiry or how approval status is observed, which keeps it from a 5.

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?

Three short sentences, front-loaded with the action, then the trigger condition, then the follow-up tool. Every sentence carries distinct, actionable information with no repetition of the title or annotations.

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 zero-parameter auth-flow step, the description supplies the essential context: precondition, out-of-band approval mechanic, and the next call to make. It leaves the caller without any indication of timing/expiry or how to detect a declined approval, which is the only meaningful remaining gap given there is no 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?

The tool takes zero parameters, so the schema-baseline of 4 applies; there is nothing for the description to disambiguate and it correctly introduces no invented inputs.

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?

States a specific verb and resource ('Creates a new login request') and immediately scopes it ('for an already identified user (no email code needed)'), which cleanly separates it from the email-code siblings like login_start/login_verify_code. An agent can tell what this does and which flow branch it belongs to without opening the schema.

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?

Gives an explicit trigger ('Use it when the session expired (SESSION_EXPIRED)') and an explicit successor ('Next: login_complete'), which is strong routing guidance. It stops short of naming a when-not-to-use case or the alternative tool by name, so it falls just below the top bar.

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