aws_get_caller_identity

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

With no annotations, the description carries the full burden, and it does disclose the underlying mechanism (an STS call) and the shape of what comes back. It does not say what happens with no valid credentials/expired session, whether the call has side effects, or whether it requires network access — gaps that matter for a credential-adjacent tool.

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 lines, front-loaded with the outcome (identity + returned fields) before the argument note. The 'Args:' block is slightly formulaic for a single optional parameter, but nothing is wasted.

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?

An output schema exists and the single optional parameter is explained, so an agent has enough to invoke this correctly. Error/permission behavior is unaddressed, which is the only meaningful omission for a one-parameter read 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 0% and the only parameter is a bare nullable string, so the description does the work: it explains that profile_name selects which profile to check and that omission falls back to the default profile. It doesn't cover behavior for a nonexistent profile name, which is the remaining gap.

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 gives a specific verb ('Get'), a precise resource ('current AWS caller identity') and even enumerates the returned fields (Account ID, IAM Role/User ARN, User ID). It is unmistakably clear what the tool returns, but it never contrasts itself with siblings such as aws_ensure_credentials or aws_list_profiles, so it stops short of the top band.

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?

It states that profile_name is optional and that the default profile is used when omitted, which implies the basic usage pattern. However there is no explicit guidance on when to call this vs. aws_ensure_credentials or aws_switch_profile, and no prerequisites (e.g. credentials must already exist) are stated.

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