design_fetch_symbol

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

With no annotations, the description carries the full burden and does a decent job: it discloses that search mode fetches no SVG, while embed mode fetches SVG, parses paths, and writes a SketchSymbolDef into the sketch — a real mutation. Gaps remain: no mention of required permissions/open-sketch state, error behavior for unapproved prefixes, or where the symbol is placed.

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?

Front-loaded with the value proposition (275k+ professional icons) followed immediately by the two-mode contract and then the constraint list. Two dense sentences, no filler; the prefix enumeration earns its space since no enum exists in 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?

There is no output schema, and the description compensates by stating that search returns a list of iconifyIds (no SVG yet) and that embed produces a SketchSymbolDef. It doesn't describe the embed-mode response or prerequisites, which for a tool with a side effect leaves a small hole.

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 the schema already documents all four parameters including the prefix-ignored-with-iconifyId rule. The description adds value only by framing the parameters as mutually exclusive modes (with the 'ph:cat' example), which is a modest increment. 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?

The description names a specific verb+resource (search Iconify icons / embed one into a sketch) and enumerates two named modes, so an agent knows exactly what the tool does. It does not explicitly differentiate itself from nearby siblings such as design_search_symbols, design_add_symbol, or design_place_symbol, which an agent could confuse with this external-library tool.

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?

It gives clear mode-selection rules: provide `query` to get a list of iconifyIds, provide `iconifyId` to embed. The approved-prefix list constrains valid input. It stops short of naming alternatives (design_search_symbols vs. this) or stating when not to use the tool, and doesn't say whether an open sketch is required.

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