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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context: it lists the fields returned and communicates the 'never guesses between accounts' policy, which helps an agent know how to map results to downstream actions. It doesn't detail pagination or limits, but those are not critical for this read-only list 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?

The description is compact and front-loaded: the first sentence states the purpose and output content, the second gives concrete usage conditions, and the third provides the critical selection rule. Every sentence earns its place and no words are 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?

For a single-optional-parameter, read-only list tool, this description is complete. It tells the agent what is returned, when to call it, and how to use the results (identify the matching account and pass unipile_account_id to the action tool). No output schema exists, but the description compensates by naming the key fields. There is no important missing context for correct invocation.

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%, with the single optional provider parameter already described as 'Optional provider filter such as linkedin, whatsapp, instagram, google, outlook or imap.' The description adds no additional parameter-level semantics beyond mentioning 'provider' in the output list, so the schema carries the burden. Baseline 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 ('List') and resource ('the user's own accounts connected to Nilyo') and enumerates the returned attributes (provider, owner display name, identifier, connection status, reconnection hints). It clearly differentiates from related account tools by focusing on listing the user's own connected accounts rather than connecting, changing plans, or checking status.

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?

Explicit usage guidance is provided: use when the user asks what is connected, when multiple accounts of one provider exist and the user names one, or after a choose_account result. It also gives a strong behavioral rule: never guess between accounts, match the user's description and pass the unipile_account_id to the action tool. This is model-level routing guidance, not just a generic statement.

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