Get Chat Limits

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

Annotations already cover readOnly/idempotent/non-destructive, and the description still adds real behavioral context: read-only even under FREE/mute/ban, no polling timer, and a full error contract (404 channel hiding, 409 reconciliation requirement, 429 no auto-retry, 501 NOT_SUPPORTED, 401 re-auth, 403 userId mismatch). The rule "Never replace an unknown send UUID/time/text" is a genuine safety constraint not derivable from structured fields.

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?

The when/when-not/auth/returns blocks are front-loaded and scannable, but the error paragraph sprawls into one dense run-on covering 404/409/429/501/401/403/API-key/rate-limit cases. Several clauses (the horizon_test_connection cross-reference, the restated 429 meaning) repeat earlier statements and dilute the signal for a read-only introspection tool.

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, so the description carries the return shape itself ({limits,capabilities,moderation,serverTime}), the auth prerequisite chain, and the failure semantics. Nothing an agent needs to call this correctly on the first attempt 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 the baseline is 3; the description goes further by explaining provenance — sign in via horizon_signin_email/anonymous and pass the resulting accessToken as sessionToken, with userId matching that signer. That is meaningfully more than the schema's "Player accessToken sent only as Bearer".

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?

"Reads five-tier bounds, current moderation and hosted capabilities" gives a specific verb and a concrete set of resources, and the Returns line enumerates the payload. The phrase "five-tier bounds" is a bit of internal jargon, but combined with the return keys the agent can tell this is a limits/capability introspection call, distinct from horizon_send_chat_message and horizon_get_chat_operation.

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" / "Not for" structure with concrete exclusions (automatic sends, repeated polling, rich-text rendering, exposing moderation credentials). It names the alternatives and the ordering: horizon_get_chat_operation to reconcile an original send, then horizon_send_chat_message for the identical replay only.

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