ocr

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

Annotations already cover the safe/read-only and closed-world profile, and the description goes well beyond them: on-device/free/private/offline processing model, an accuracy caveat ('small or unusual text can be misread; check numbers that matter'), and the exact return shape (line-by-line text or a prompt answer). That is the kind of behavior an agent needs before deciding to trust the output.

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 dense sentences, front-loaded with the action and inputs, then return behavior, then caveats. No filler; each clause carries a constraint or capability an agent must know.

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 still describes the return value (line-by-line text or a prompt-driven answer) and the failure mode (misread text). For a two-parameter read tool with full schema coverage and annotations, nothing material is missing.

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 baseline is 3, but the description adds real meaning the schema lacks: accepted formats are constrained (PDFs explicitly unsupported, absolute path required) and the empty-prompt case is spelled out as 'return all the text' rather than an answer.

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 the text in an image file') with example inputs and the underlying engine. It also distinguishes itself from siblings by excluding code review and reasoning, which would otherwise collide with classify/extract/summarise.

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 states when the tool applies (image files, absolute path) and key exclusions ('PDFs are not supported', 'Not for code review or reasoning'). It does not name a specific sibling to use instead for those excluded cases, so the routing guidance is clear but not fully closed.

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