glass_a11y_snapshot

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

Discloses deterministic, low-token behavior, error conditions (no accessibility tree, e.g., canvas apps), and that it works with screenshots. With no annotations, the description fully covers behavioral expectations.

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 purpose, then details. No filler; every sentence adds essential information.

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, output format, error handling, integration with other tools, and use of output. Adequate for a zero-parameter tool with no output schema.

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?

Tool has no parameters, so baseline is 4. Description adds value by explaining how to use output IDs and the line format, which indirectly informs parameter usage (none needed).

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?

Clearly states it captures the active window's accessibility tree as compact text, specifying the output format and its role alongside screenshots. Distinguishes from sibling tools like glass_screenshot by mentioning fallback behavior.

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?

Explicitly tells when to use (alongside screenshots), what to do on error (fall back to glass_screenshot), and how to use the output (pass #id to glass_click_element). Provides clear context for selection.

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