read_file

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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavior: results come back in document order as paginated character windows, and images/audio/video yield no text at all. It doesn't mention any size or rate limits beyond the schema's max_chars cap.

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 short sentences, front-loaded with the core action, then scope, then the important caveats. No sentence is filler; even the closing line about pictures and audio prevents a wasted call.

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 carries the burden of explaining returns, and it does: ordered text in max_chars pages. A note on what happens when the offset exceeds the content, or confirmation that next_offset is returned, would close the last 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 75% and the schema already documents path, code and offset well. The description reinforces the pagination model ('in pages of max_chars') and the search-derived origin of paths, but adds nothing about how offset/next_offset chains together or how max_chars should be tuned.

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 ('Read all the text of one of the user's Mac files') and scopes it to DigUp-extracted text from PDFs, documents, slides and sheets. It does not explicitly distinguish itself from the sibling read_passage, which is the main remaining ambiguity for an agent choosing between the two.

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?

'Use it for paths from a digup search, which don't exist on this machine' gives a clear positive condition and heads off a likely mistake (treating the path as a local filesystem path). It offers no explicit exclusion or alternative for when read_passage would be the better choice.

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