snapshot

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

Annotations already declare readOnlyHint and openWorldHint, so the description needn't restate safety, and it adds real context instead: the line format, iframe inlining, and the fact that the footer signals when paging with offset is needed. It doesn't explain truncation behavior or the role of max_chars, which is the main missing piece.

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?

One dense paragraph, front-loaded with what the tool returns, then modes and paging. Nearly every clause carries information, though the running sentence structure makes the paging rule easy to miss.

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 6-parameter read tool with no output schema, it explains the return shape and the mode choice well. However, two parameters (max_chars, viewport_only) are left semantically empty, and truncation behavior — central to a 'compact' snapshot — is only gestured at via the footer hint.

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%: tab, scope, and offset are documented in the schema, while mode is documented by the description's interactive/full explanation. max_chars and viewport_only are unexplained in both places, leaving the description's compensation incomplete.

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: 'Compact accessibility snapshot of a tab', and describes the output shape (one line per element, indented by nesting, iframes inlined). That pins down the operation precisely. It never contrasts itself with siblings like read, find, or screenshot, which could otherwise look like plausible alternatives for inspecting a page.

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?

It gives partial selection guidance: interactive is the default vs full 'adds text, lists, tables, images', and 'Page with offset when the footer says so' hints at paging. But there is no explicit statement of when to prefer snapshot over read/find/screenshot, nor any prerequisites.

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