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

Annotations already declare this is a non-idempotent, non-destructive write in a closed world. The description goes beyond that by disclosing the eligibility gate (active Forge access), that past sessions are silently skipped, and that the result distinguishes an automatic calendar invite from a manual add by Ben.

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: the action and its phase/quarter inputs come first, then the constraints, then the return semantics. Every clause carries information and nothing is padding.

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 no output schema, the description carries the return-value burden and does so by explaining that the answer reports whether the calendar invite was sent or Ben adds it manually. Combined with the eligibility and filtering details, an agent has everything needed to call this correctly.

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 already 100% with the phase enum documented, so the baseline is 3. The description adds real meaning by clarifying that phase="all" means the whole cohort from now on, which sharpens the temporal semantics of the choice.

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: joining the signed-in person to Pirate Forge live sessions, with the scope parameterized by phase. An agent can distinguish this from register_for_event, book_hour_with_ben, and my_forge_sessions without opening a schema.

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?

It routes the agent to my_forge_sessions as the source of the quarter key and states the eligibility precondition (active Forge access) and the temporal filter (only future sessions are added). No explicit when-not or alternative named, but the context is clear enough to select correctly.

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