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

No contradiction with the readOnlyHint and idempotentHint annotations; the description reinforces a safe read operation. It adds the workflow context and the 'all available' scope, but does not disclose further behavioral traits such as response format or ordering, though that burden is reduced given the annotations and output 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?

Two sentences, front-loaded with the core purpose followed by a helpful usage chain. No redundant phrasing or filler, earning a top score.

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?

Given the zero-parameter signature, strong annotations (read-only, idempotent), presence of an output schema, and a concise workflow hint, the description provides all necessary context for an agent to select and invoke this tool safely. No significant gaps remain.

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 tool takes zero parameters, and the schema is fully self-contained with no description coverage needed. Since there are no inputs to explain, the description's silence on parameters is appropriate; baseline of 4 applies.

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 opens with 'List all available diagram providers,' which clearly states the action (list) and resource (diagram providers) with concrete examples. It distinguishes this tool from siblings like list_nodes and list_services by establishing the provider-level scope and the browsing chain. This is a specific, non-tautological purpose statement.

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 explicitly provides a navigation path: 'Use list_providers -> list_services -> list_nodes to browse available node types for a specific provider.' This tells the agent when to invoke this tool (as the entry point) and how it fits with related tools, though it does not state exclusions or when to prefer list_categories.

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