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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds behavioral detail beyond that: the compact flag changes the returned shape to id + name only, and the result feeds set_theme. It omits pagination/ordering behavior, but for a small curated list that is minor.

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?

Three short clauses, zero filler, front-loaded with what a preset is and followed by the two facts an agent needs: the compact output shape and the consuming tool.

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 no output schema, the description usefully states the return shape under compact, and it links the tool to its consumer set_theme. It does not explain the mood filter's semantics or whether presets are site-scoped, but the schema covers the filter and the tool is simple enough that little else is required.

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 coverage is 100%, so the schema already documents mood, brief, and compact. The description restates the compact behavior ('id + name only') without adding syntax or format detail, so it neither compensates for nor exceeds the schema. Baseline 3 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?

States a specific resource and its contents ('Curated theme presets (palette + fonts + tokens)'), which distinguishes it from siblings like list_templates and suggest_palettes. It is clear what the tool returns, though it never uses the verb 'list' explicitly in the description body.

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?

Names the downstream action explicitly ('set_theme({ preset }) applies one'), which tells the agent why to call this tool and what to do with the result. It does not, however, contrast itself with sibling discovery tools such as suggest_palettes or list_templates, so the routing is only partial.

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