browser_take_screenshot

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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false), so the bar is lower. The description adds one meaningful behavioral trait beyond annotations: the screenshot is a passive artifact that cannot drive actions. However, it leaves file-saving/output behavior to the schema's filename parameter rather than disclosing it in prose.

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, each earning its place: the first states the operation, the second carries the critical usage caveat and sibling routing. No filler or repetition of schema content.

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 read-only tool with a 100%-coverage schema and safety annotations, the definition is nearly complete: purpose, key caveat, and alternative routing are all present. A somewhat richer description could orient agents toward element/fullPage screenshot capabilities, though the schema already documents these.

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%, with detailed documentation for all six parameters including enum semantics (type, scale), defaults, and interaction constraints (fullPage cannot be used with element screenshots). The description adds nothing beyond the schema, so the 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 states a specific verb and resource ('Take a screenshot of the current page') and distinguishes itself from a sibling by noting 'use browser_snapshot for actions.' The action and scope are unambiguous, and the read-only intent matches the title.

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 description explicitly tells the agent when NOT to use this tool ('You can't perform actions based on the screenshot') and names the exact alternative ('use browser_snapshot for actions'). This is direct when/when-not routing with no inference required.

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