set_scale

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

With no annotations provided, the description carries the full burden and does so thoroughly: it discloses coordinate conventions (image px at render scale 2.0, origin top-left, y down), the relationship between PDF pt and px, and that the detected scale is never auto-applied. It also emphasizes the 'exactly ONE of' constraint, which is behavioral and not fully enforced by the schema.

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?

The description is compact and front-loaded with the core action and mode list, followed by crucial coordinate context. Each sentence serves a distinct purpose, and there is no redundant information, achieving high informational density in a small space.

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?

The description covers all necessary behavioral aspects: modes, coordinate system, explicit adoption of detected scale, and note about sheet payloads. Since an output schema exists, return values are not needed. It is complete enough for an agent to use the tool correctly without ambiguity.

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?

The input schema already describes each parameter, but the description adds significant meaning by explaining the coordinate system (px, pt, origin) that is essential for calibrate and upp, and by clarifying the semantic relationships between the mutually exclusive modes. This goes beyond the schema descriptions, which only cover basic purpose.

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 explicitly states 'Set a sheet's scale' and enumerates the four mutually exclusive modes (label, upp, calibrate, use_detected), making the tool's function unambiguous. It also distinguishes it from sibling tools like sheet_info or view_sheet by focusing on the setting aspect.

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 provides clear context for when to use this tool: it is the explicit call to set scale, and it notes that the detected scale is never applied automatically, which informs when use_detected is appropriate. However, it does not explicitly mention alternatives for merely reading scale (e.g., sheet_info), leaving some implicit guidance.

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