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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful context beyond that: the value is live ('online') and will change if set_network_profile runs or phone.json is edited, which tells the agent the result is not a stable cached constant. Return shape is not described, but that is minor for a single-value getter.

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?

A single sentence with the core action front-loaded and the freshness caveat attached parenthetically. Nothing is redundant and nothing needs to be re-read.

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 one-parameter read-only getter with annotations covering safety and a fully documented schema, the description supplies what an agent needs to call it correctly. The only gap is that it never states the return type (presumably a profile name string), which is largely inferable from the wording.

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?

There is one required parameter, session, and schema coverage is 100% with the schema itself documenting it as 'Session from open_app.' The description adds no further parameter detail, which is acceptable given the schema already does that work; baseline 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?

The description opens with a specific verb and resource: 'Read the phone's current network profile name.' That is unambiguous and it names the mutating sibling set_network_profile in the parenthetical, so an agent can distinguish read from write. It falls just short of 5 only because the sibling distinction is implied through the freshness clause rather than stated as a routing rule.

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 parenthetical implies this is the read path and that set_network_profile is what changes the value, which gives the agent enough context to pick it for inspection rather than modification. There is no explicit 'use this when' statement and no exclusion of alternatives beyond the single named setter.

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