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

Annotations declare readOnlyHint=false and destructiveHint=false (a non-destructive write); the description goes beyond them by disclosing the auth requirement and the returned session_id that other calls depend on. It doesn't state the response shape or failure modes, but for a write tool with annotations, this adds real value.

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 tight sentences with zero waste; the action is front-loaded and the dependency/auth facts follow immediately.

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 session-initiation tool with no output schema, the description covers what an agent needs: the action, the returned session_id, and the auth requirement. Minor omission is any note on session lifetime or errors, but nothing essential is missing.

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 both parameters (name, url) are already fully documented in the schema, including the url scrape behavior. The description adds no additional parameter meaning, so the baseline 3 applies.

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 a new physical-operator onboarding session.' The scope ('physical-operator onboarding') is specific enough to place it within the pcc_onboard_session_* family, though it doesn't name sibling tools like pcc_onboard_session_status to distinguish itself explicitly.

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?

Clear context: it returns a session_id 'used by every subsequent /api/onboard/* call,' which tells the agent this must be invoked first. There are no explicit exclusions or named alternatives, but the sequencing requirement is effectively conveyed.

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