wait_for_change

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

With no annotations, the description carries the full behavioral burden. It helpfully discloses the change-detection algorithm and that it 'returns the new frame', but is silent on the most important behavioral question: what happens on timeout (default 3000ms) — does it raise, return, or return the stale frame?

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, front-loaded sentence with zero filler. It packs the purpose, mechanism, and return value efficiently, though the parenthetical grid detail could arguably be trimmed.

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?

Covers purpose, detection mechanism and return value for a 2-param tool with no output schema. However, missing timeout semantics and relying on defaults that aren't explained leaves meaningful gaps for an agent invoking it.

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 0%, so the description must compensate. It partially explains 'threshold' (luma difference on a 32x18 grid), but 'timeout_ms' is never described or referenced, leaving half the parameters undocumented in both schema and description.

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 resource ('the screen changes') and even exposes the detection mechanism (mean luma difference >= threshold on a 32x18 grid). This clearly separates it from the fixed-duration sibling 'wait_for', though it does not name that sibling directly.

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 implied by the semantics of waiting for a screen change, but there is no explicit when-to-use vs when-to-use-alternative guidance and the closely related 'wait_for' sibling is never mentioned or differentiated.

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