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 usefully adds the failure mode ('Fails with code timeout') and the return ('Returns the snapshot'), which are real value-adds, but it omits matching semantics (substring vs exact) and default timeout 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 condition, the inverse-mode flag, the failure mode, and the return value are all front-loaded and each clause 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?

With four parameters, no output schema, and only half the params documented in the schema, the description covers the essentials (what it waits for, the gone inversion, error code, returned snapshot). It still leaves text-matching behavior and the timeout default implicit, which matters for correct invocation.

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 50%: session and timeout_ms are documented in the schema, while text and gone are not. The description compensates by explaining gone: true inverts the wait, but leaves the matching semantics of text (substring? case-sensitive?) undefined, so meaning is only partially added.

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 ('Wait until') and a precise condition (text appears, or is gone when gone: true) scoped to the phone browser's page. It is clearly distinguishable from siblings like browser_snapshot or browser_click, though it never names an alternative explicitly.

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 is for waiting on dynamic content rather than reading state. There is no explicit when-to-use/when-not guidance or pointer to browser_snapshot as the non-waiting alternative.

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