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

Annotations already declare this is a non-destructive, open-world mutation. The description adds real value by disclosing the confirmation gate ('Requires confirmation: true to create the session') and the underlying REST endpoint. It does not explain what a started session returns (session id? first question?) or what happens if a session already exists, so the behavioral picture stays incomplete.

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, front-loaded with the action and input. 'Mirrors POST /api/onboarding/start' earns less of its place than the confirmation requirement, but it is one clause and aids debugging.

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?

With annotations and a fully described 4-param schema, the core call contract is covered. What is missing is the outcome: nothing tells the agent that starting yields a session handle needed by submit_onboarding_answer or get_onboarding_session, which is the obvious next step an agent must take.

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%, so all four parameters are already documented, including the confirmation gate and the idempotency-key caching behavior. The description only restates situationText and confirmation, adding no syntax, format, or length guidance beyond the schema.

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 ('Start an onboarding session') and names the input it consumes ('from situation text'). It implicitly distinguishes itself from resume_onboarding and commit_onboarding via the word 'start', but never explicitly routes the agent away from those 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?

Usage is implied rather than stated: it is the entry point that takes free-text situation input, and it names the confirmation prerequisite. There is no explicit 'use this instead of resume_onboarding when…' guidance and no note on what to do after starting.

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