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

The description adds useful context beyond the annotations by explaining that user-scoped sessions are stored encrypted in PostgreSQL while legacy local sessions use the AWS filesystem cache. However, it does not explain why the operation is non-read-only, what side effects polling may have, or whether there is a required polling cadence.

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 concise and front-loads the primary action in the first sentence. The second sentence adds storage context without excessive length, though it is somewhat tangential to the immediate 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?

The output schema and annotations cover return values and safety signals, and the input schema fully documents the parameters. Still, the description does not route the agent among the several SSO login siblings or explain the expected polling lifecycle, which are meaningful gaps for an authentication tool.

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%, and both parameters are fully documented in the input schema. The description does not add meaning beyond the schema, so the baseline score 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 uses a specific verb and resource: polling the device_code status and verifying that AWS role credentials are usable. It is clear what the tool does, though it does not explicitly differentiate itself from siblings such as aws_sso_login_device_start or aws_sso_login_global_poll.

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 'Poll the device_code status' implies this is a follow-up step after obtaining a device_code, but the description does not explicitly say when to use it, when not to use it, or how it relates to alternative SSO login tools.

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