list_accounts

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

Goes well beyond the read-only annotations by disclosing that remote token validity is not checked, that an enrolled account can still fail with reauth_required, and that the required account argument is ignored. These are exactly the operational caveats an agent cannot infer from the schema or annotations.

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?

Four short sentences, front-loaded with the purpose and the call-first directive, followed by the two caveats. No filler.

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, and the description still names what is returned; it also flags the reauth_required failure mode. An agent has everything needed to call it correctly and interpret the result.

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 coverage is 100%, so the baseline is 3, but the description adds real meaning: it explains the surprising fact that the required account argument is ignored and any configured alias may be passed, resolving a potential mismatch with the schema's 'selects which mailbox to use' wording. It could have reconciled the single-value enum ('inspection') with 'any configured alias' more explicitly.

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 ('List configured account aliases') and enumerates the returned fields (email addresses, local enrollment state), which clearly separates it from the message/thread/label siblings.

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?

'Call first to pick the account alias for every other tool' is an explicit sequencing instruction that tells the agent when this tool must be used and why, relative to all other tools.

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