render_diagram

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 well: it discloses file-writing side effects ('Writes output_path'), the exact JSON report structure ('status' with its four possible values, plus 'summary'), and the hint/repair mechanism. The only gap is not stating whether an existing output_path file is overwritten or whether rendering is destructive to input.

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?

Four sentences, each earning its place: purpose, behavior, warning-handling workflow, and sibling routing. Purpose is front-loaded. It is compact for a 14-parameter tool and avoids redundancy with the schema.

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 complex tool with 14 parameters, no output schema, and no annotations, the description covers the critical workflow well: return format, status values, hint loop, and preset selection. It doesn't explain every parameter, but the schema covers 79% of them and the core rendering/checking loop is fully specified.

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 description coverage is 79%, so the schema already documents most parameters in detail (preset enums with platform notes, output_path formats, diagram syntax). The description adds workflow-level context (pick preset by destination, run check first) but adds little param-level semantics beyond what the schema provides, so the baseline 3 is appropriate.

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 ('Render'), resource ('ASCII/Unicode box diagram'), and output format ('as SVG (or a web page)'), plus a precise constraint ('keeping every character in its exact cell'). This clearly differentiates it from the sibling check_diagram, whose purpose is validation, not rendering.

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 directs the agent to 'Run check_diagram first on a new diagram', naming the alternative and the precondition that selects it. It also gives concrete workflow guidance for post-render handling ('For warnings, apply each hint... and render again') and parameter selection ('Pick preset from where the diagram is going'). Nothing is left to inference.

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