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

Annotations already flag destructiveHint=true and readOnlyHint=false, so the description earns credit for adding context annotations cannot: "Sends nothing" rules out outbound messaging, and "the conversation's follow-up date is cleared when nothing else is open" discloses a side effect on adjacent state that would otherwise surprise an agent. It does not say whether the close is reversible or what happens if no open follow-up exists.

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 sentences, front-loaded with the action and outcomes, then identification, then domain mapping and side effect. Dense but every clause carries information; the parenthetical lists make individual sentences heavy, which costs a point on readability.

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 5-parameter, 0%-schema-coverage mutation with no output schema, the description covers outcome semantics, both identification routes, and the main state side effect. Remaining gaps — precedence between identifier params, behavior when nothing is open, and the response shape — are minor but real for a destructive operation.

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 0%, so the description must carry the load, and it does for the most important parts: it glosses the outcome enum ("done (it happened) or cancelled (no longer needed)") and groups the four identification params into either a follow_up_id or a conversation identifier set. It leaves precedence unspecified when both an ID and a conversation identifier are supplied, and says nothing about the name param's matching behavior.

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 ("Close an open follow-up reminder") and immediately enumerates the two valid outcomes, which cleanly separates it from the sibling set_follow_up that creates or reschedules one. An agent can tell exactly what this does without opening the 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?

Gives two concrete invocation paths — supply a follow_up_id, or supply a conversation (conversation_urn, contact_id, or a person's name) — and names the sibling tools where those IDs come from (list_follow_ups, read_conversation, get_contact). It also maps the action onto the Quibbly UI (Done or delete). It stops short of an explicit exclusion, e.g. pointing to set_follow_up when the reminder should be rescheduled rather than closed.

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