preview_diagram

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

Annotations already declare readOnlyHint false and openWorldHint true, signaling a non-read-only, external-interacting operation. The description adds that it opens an HTML preview in the browser, which aligns with openWorldHint, but does not clarify permissions, temporary file side effects, or rate limits. It offers modest context beyond the annotations.

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?

Two sentences plus a routing pointer, front-loaded with the primary action and output medium. Every sentence earns its place; the syntax pointer prevents misuse and is not redundant.

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 simple preview tool with full schema coverage and no output schema, the description covers the essential behavior and optional features. It omits usage comparisons, but overall it is complete enough for correct invocation.

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 100%, so all four parameters are fully documented in the schema. The description mentions theme toggle and optional source display, mapping to theme and include_source, but adds no format or syntax detail beyond what the schema provides. 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') and resource ('DGMO diagrams'), and names the output medium ('open an HTML preview in the browser'). It does not explicitly distinguish from siblings like render_diagram or open_in_app, but the scope is clear enough for selection.

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 a pointer for syntax ('call get_language_reference'), which is a prerequisite note rather than when-to-use guidance for this tool. There is no explicit comparison to alternatives like render_diagram, share_diagram, or open_in_app; usage is only implied by the tool name and purpose.

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