switch_login

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

With no annotations, the description carries the full burden and does so: it discloses the exact side-effect sequence, what is returned (session model, hardware/firmware), what is deliberately withheld (cookies), and two refusal/blocking conditions including the circuit breaker needing human reset. This is unusually rich behavioral disclosure.

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 tight sentences with the action sequence front-loaded, then returns, then refusal conditions. Every clause carries operational information; nothing is padded or redundant.

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?

No output schema exists, yet the description explains the return payload (session model, hardware/firmware, no cookies) and the failure modes. For a 0-param, no-annotation tool this covers everything an agent needs before invoking.

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 there is nothing to disambiguate; baseline for a 0-param tool is 4. The description adds no parameter detail, which is appropriate here.

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 ('Perform exactly one login') plus the full composite sequence (confirm via data GET, then log out). It is clearly distinguishable from siblings like switch_logout and switch_check_auth, which do only one of those steps.

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 concrete conditions under which the tool will not act ('Refuses (no POST) in restored-account or encrypted-variant modes') and notes the breaker blocks it after a prior failure until a human clears it. It does not explicitly contrast with switch_check_auth or switch_status, but the precondition context is clear.

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