build_sign_in_payload

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

No annotations are provided, so the description carries the behavioral burden. 'Build ... from raw credentials' and 'Returns the payload' imply a local, pure construction with no auth or state mutation, which is useful. It stops short of confirming there are no side effects or network calls, and says nothing about failure conditions for invalid credentials.

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?

Two short sentences with no filler; the purpose is front-loaded and the downstream consumer is stated second. Every clause carries information.

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?

With six parameters, five required, and no output schema, the description does usefully state that the return value is the payload for managed_sign_in. It still omits the input dependency on a generated session keypair and any description of payload shape, so it is adequate but leaves clear gaps.

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 all six parameters (apiKey, userId, sessionKey, nonce, signature, refSourceCode) are already documented in the schema. The description adds only the collective phrase 'raw credentials' and no per-parameter meaning, so the baseline of 3 is appropriate.

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 and output ('Build the encrypted sign-in computedData payload from raw credentials'), so the agent knows exactly what is produced. It also ties the result to the sibling managed_sign_in. It does not distinguish this from other sign-in artifacts such as generate_session_keypair, which produce one of its inputs, so the sibling differentiation is only partial.

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?

'Returns the payload to use with managed_sign_in' implies a build-then-submit ordering, which is usable guidance. However, no prerequisites (e.g. that sessionKey comes from generate_session_keypair), no when-not-to-use, and no alternative are named, so usage is only implied rather than stated.

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