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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety bar is low. The description still adds real value by asserting the data is built-in and needs no project access, which explains why the call succeeds in an unauthenticated/empty context; it stops short of stating cost, latency, or response size.

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, zero preamble, with the core identity front-loaded and the content inventory second. The second sentence is a dense list rather than padding, though it could have carried the symbol-vs-feature behavior instead of only enumerating definition categories.

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?

An output schema exists, so return-format explanation is rightly omitted, and access requirements are covered. What remains missing is the two-step workflow the tool implies — call once to read the index, then again with a 'symbol' — which matters for an agent planning a lookup sequence.

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?

With 50% schema coverage, the description partially compensates: it names the four feature values ('screenshots, social graphics, promo videos or mockups') matching the feature enum. However, it never explains the interplay between the two parameters — whether omitting 'symbol' returns the whole index, and whether 'symbol' narrows output to a single definition — leaving the primary caller decision undocumented.

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 and resource ('Returns the built-in editing reference') and enumerates exactly what the payload contains: symbol index plus field, enum, coordinate, validator and catalog definitions. No sibling tool serves this lookup role, so the definition is unambiguous on its own.

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 establishes prerequisites ('available without project access or external resource browsing') but never says when an agent should call this instead of proceeding directly, nor that it is the discovery step preceding schema-dependent calls like save_layout or update_graphics_settings. Usage is implied by the resource name rather than stated.

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