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

Annotations only declare readOnly=false, destructive=false, openWorld=true; the description adds real value beyond them by disclosing the notify email side effect, that both slot IDs are returned, the default per-call confirmation and its opt-out, and the external 'reaches other people' effect with an explicit confirm-with-user rule. The Cotlet API key access requirement is also surfaced. Not a full 5 because some of this overlaps with the openWorld annotation and no rate-limit/failure behavior is described.

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?

Purpose is front-loaded and easy to scan, but the second sentence re-states the first ('from their slot to another open slot on the same sign-up' vs 'to a slot that still has room, on the same sign-up'), repeating 'same sign-up' twice. The trailing sentences about confirmation, external reach, and API key are packed run-on style rather than cleanly structured.

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 mutating, open-world tool with no output schema, the definition covers the essentials: what it changes, the email side effect, that both slot IDs come back, the confirmation default, and the auth requirement. Return-value detail beyond the two slot IDs is thin, but no output schema exists so that is acceptable.

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 (including notify's email/default semantics) are already documented in the schema. The description's sentence 'With notify on, the participant gets an email' largely restates the notify schema description, adding little beyond the 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 (move), resource (participant), and precise scope: from their current slot to another open slot on the same sign-up. Reinforced by the constraint that the target slot must still have room and be on the same sign-up, which cleanly distinguishes it from siblings like add_participant, remove_participant, or update_slot.

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?

Gives clear context for when to use it (moving one participant to a slot with room, same sign-up) and adds a strong operational condition: confirm with the user before each call because it reaches other people. However, it never names an alternative sibling for the adjacent case (e.g., remove/add participant), leaving the routing inference incomplete.

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