Screenshot terminal

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), yet the description adds real behavior: height is always term.rows, output is inlined as base64 unless filePath is set, and images over 2097152 bytes are auto-spilled to a temp file. That spill behavior is the kind of non-obvious side effect worth crediting, though no pagination or size limits on page depth are discussed beyond the schema's clamp note.

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?

Three sentences, each front-loaded and earning its place: output format first, then paging semantics, then file/inline behavior. No filler or restatement of the name.

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 no output schema, the description does carry the return-value burden and handles it: path returned when filePath is set, base64 otherwise, temp-file spill for large images. Combined with annotations covering safety, an agent has what it needs; only the absence of any guidance on choosing between text readers and screenshots is a slight gap.

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 100%, so the baseline is 3, but the description adds semantics the schema lacks: page windows are rendered 'at the same dimensions as the live screen,' clarifying that paged screenshots are dimensionally consistent with page 0. That is a genuine addition beyond the parameter's own text.

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 and resource with output format: 'Render a screen-sized window of the terminal to a PNG.' This distinguishes it cleanly from terminal_read (text extraction) and other siblings without needing to name them.

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 explains how to use `page` to walk scrollback, which is useful operational context, but it never states when to choose this tool over terminal_read or terminal_scroll for retrieving terminal content. Usage is implied rather than routed.

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