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

readOnlyHint=true already tells the agent this is a safe read, lowering the burden on the description. The description adds only the 'latest' (most-recent-snapshot) semantics and a redundant REST path; it says nothing about the shape of the returned payload, whether an empty result is possible, or rate-limit/error behavior.

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 short sentences with zero filler; the purpose is front-loaded and the endpoint reference follows as secondary detail. Every sentence earns its place.

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 single-parameter read tool with annotations covering safety and a fully documented schema, the description is adequate but thin: with no output schema, it should say more about what 'device/app info' actually contains, so an agent knows whether the response is the right data for its task.

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 100% and the schema already documents user_id as a Vital UUID, so the description need not repeat it. The description adds no further parameter meaning, so the baseline of 3 applies.

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?

Names a specific verb (Get) and resource (a user's latest reported device/app info), plus the underlying endpoint GET /v2/user/{user_id}/info/latest. It is distinguishable from siblings like vital_get_user or vital_get_profile, though it never explicitly contrasts itself with them.

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?

Usage is only implied: an agent can infer this retrieves the most recent device/app report for a given user, but there is no statement of when to prefer it over vital_get_user, vital_get_profile, or vital_get_user_connected_providers, and no prerequisites or exclusions.

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