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

With destructiveHint=true, idempotentHint=false and openWorldHint=true already declared, the description still contributes meaning: 'atomically' tells the agent the operation is all-or-nothing and that accounts are created as a side effect. It does not state reversibility or what happens on partial failure, but the safety profile is covered by 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?

Three short sentences, zero padding: purpose and atomicity first, the API mirror second, the hard precondition last. Nothing is repeated needlessly beyond the confirmation gate.

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 destructive, non-idempotent mutation with no output schema, the agent is left guessing what comes back (the created accounts? the finalized session?) and whether the session remains usable afterward. Atomicity is the main thing conveyed; the return contract and post-state are not.

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 all three parameters are documented in the schema, including the optional idempotencyKey's 24h cache semantics. The description restates the confirmation requirement without adding syntax or format detail, so this is baseline.

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 ('Finalize an onboarding session') plus the concrete side effect ('create detected accounts atomically'), so an agent knows exactly what happens. It does not differentiate itself from the very similar commit_work_session and commit_import siblings, which an agent must infer from the 'onboarding' scope alone.

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?

'Requires confirmation: true' is a real precondition, but the schema already says 'Must be true to execute the mutation', so it adds little. There is no explicit statement of when to call this versus resume_onboarding, submit_onboarding_answer, or commit_work_session, leaving ordering to inference.

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