place_count

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

Annotations are absent, so the description fully carries the burden and does so thoroughly. It discloses the exact computed shape ({count: 1}), the single-undo-step behavior, coordinate system conventions (image px, render scale 2.0, origin top-left, y down), and how results appear in takeoff_summary and the marked set.

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 dense and every sentence adds unique information, from core purpose to coordinate details. It is front-loaded with the primary function. While somewhat long, the length is justified by the complexity of coordinate systems and undo behavior.

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 an output schema present, return values need not be described. The description covers operational behavior, coordinate transformations, undo grouping, scale requirement (none), and how the results are reported. For a 3-parameter tool with an array parameter, this is highly complete without obvious gaps.

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 covers 67% of parameters (points and condition have descriptions). The description adds critical meaning for 'points' by specifying the coordinate system (render scale, origin, y-down) and for 'condition' by explaining finish-tag commitment. The 'sheet' parameter lacks schema description but the description mentions dimensional payloads, partially compensating.

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 clearly states the tool's function: 'Count markers' with one count shape per point. It distinguishes itself from siblings by identifying the 'scale-free quantity family' and explicitly stating 'NO scale required', contrasting with measure tools like measure_line or measure_surface.

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?

Provides clear context for when to use this tool: counting EA items (thresholds, stair nosings, etc.) that are counted as each, not measured. It explicitly states no scale is required, implying it is for use without scale, but does not name specific alternative tools or explicitly exclude edge cases.

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