system_version

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

Annotations already establish readOnly/idempotent/non-destructive and closed-world, so the safety burden is lifted. The description adds genuine behavioral value: it discloses the resolved `gate.tier` values (blocking/recommended/ok/unknown) and that resolution is done server-side so the agent needn't compare versions itself. Missing only auth/rate-limit or caching notes.

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?

Two sentences, front-loaded with what is returned and followed by the conditional behaviors. No filler, no restatement of the tool name, and every clause carries a fact the agent needs.

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?

There is no output schema, so the description must carry the return contract; it covers the full payload, the flat `client` object, store URLs, and the `gate.tier` resolution with its value set. That is sufficient to call the tool correctly, with only minor gaps around the exact shape of the full payload.

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, but the description adds semantics the schema does not: it names the output shape each parameter produces (`client` object, `gate` with `tier`) and enumerates the tier values. The `version`-requires-`platform` dependency is repeated from the schema, which is the only redundancy.

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?

Specific verb (Get) plus a precisely enumerated resource: backend version, web/mobile latest+min versions, store URLs. The scope is unlike any sibling (system_health, admin_version_overrides), so an agent can identify it 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?

The description clearly explains the two usage modes: omit platform for the full payload, supply platform to get a flat `client` object, and add version to obtain a resolved `gate`. It stops short of naming an alternative tool or stating when not to use this one, so it is context-rich but not fully exclusive.

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