accept group invite

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

Goes well past the annotations: discloses that the exact invitation is consumed, limits/blocks are rechecked, the issuer is notified, and that same-revision replay cannot produce a second effect — consistent with idempotentHint=true and destructiveHint=true rather than contradicting them. Adds concrete HTTP-status semantics (409 revision conflict, REQUEST_NOT_FOUND, INBOX_FULL rollback, 429 no retry) that annotations cannot express.

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?

Front-loaded with purpose then clearly labeled sections (Use when / Not for / Requires / Side effects / Returns / Errors), making it scannable despite its length. Minor redundancy in the error tail, where 429 and the 401/HORIZON_API_KEY case are restated.

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?

No output schema exists, yet the description specifies the return shape ({groups: MyGroupsView, group: GroupView|null}), the privacy scope of groups, and the cache-invalidation instruction. Auth, side effects, idempotency, and failure reconciliation are all covered for a destructive 5-param mutation.

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%, but the description adds operational meaning: how to obtain sessionToken (sign in via horizon_signin_email/horizon_signin_anonymous and pass the accessToken), and that expectedRevision must be the reviewed revision and requestId the exact pending identity. Slight redundancy with the schema's own hints, hence not a 5.

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+resource: applies the accept-group-invite action against a reviewed group revision, and that it consumes the player's exact invitation. It does not explicitly distinguish itself from nearby siblings horizon_accept_group_request or horizon_decline_group_invite, so the agent must infer invite-vs-request semantics from the name alone.

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?

Explicit 'Use when' and 'Not for' clauses name the triggering condition (player explicitly confirms the action) and three exclusions (replacing reviewed revision/requestId, bypassing a leader's block, automatic retry after uncertainty). It also routes reconciliation to horizon_get_groups and horizon_get_group_pending.

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