Get Shared Object Owner Usage

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

Goes well beyond the readOnly/idempotent annotations, disclosing that absent revision/count read as zero without writing, that 409 requires manual reconciliation rather than automatic retry, that 404 is deliberately ambiguous, and that 422 preserves existing data. It also covers the full error surface (401 vs 403 token/user mismatch, 429 rate limit, HORIZON_API_KEY failures via horizon_test_connection).

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 the purpose, then cleanly sectioned into Use when / Not for / Requires / Side effects / Returns / Errors, so an agent can scan selectively. The error paragraph is dense and includes some boilerplate that applies to every tool in this server, which slightly dilutes density.

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 supplies the return shape ({userId,collection,revision,count,limits,pollAfterSeconds,serverTime}), plus auth, side effects and the failure matrix. Nothing an agent needs in order to call this correctly and handle its responses 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 3 is the baseline; the description earns above that by explaining sessionToken provenance (the accessToken returned by a sign-in call) and the 403 consequence of a userId/session mismatch, which the schema does not state. The 'one collection' phrasing also clarifies the collection parameter's granularity.

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: reads the current player's count and creation precondition for one collection, which is distinguishable from object-reading siblings like horizon_get_shared_object and horizon_query_shared_objects by its per-collection aggregate scope. It stops short of naming those siblings explicitly, so an agent must infer the boundary from scope wording 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?

Both sides are spelled out: 'Use when: explicit world-map/async-PvP object access after reading horizon://docs/shared-objects' and an explicit 'Not for' list excluding background polling, automatic page traversal, opaque-byte interpretation and combat validation. The auth prerequisite also routes to concrete alternatives (horizon_signin_email / horizon_signin_anonymous).

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