Run raw ExtendScript in Illustrator

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

With no annotations, the description carries the full burden. It discloses that the tool executes arbitrary code, notes the language is 'roughly ES3', and explains the return value behavior ('value of the last expression ... returned as a string'). It also lists relevant object model areas (app, documents, PathItem, etc.). While it doesn't warn about destructive side effects, 'arbitrary' and 'anything' convey broad capability. This is solid disclosure for an escape-hatch tool.

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 concise sentences cover action, usage, return semantics, and object model references. No filler or repetition. The most important information is front-loaded and every sentence earns its place.

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 tool with a single parameter and no output schema, the description is nearly complete: it explains what it does, when to use, and how to get results. The only gap is error handling or exception behavior, but that's a minor omission for an arbitrary-code tool. The object model docs reference further helps the agent craft scripts without external lookup.

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%: the 'script' parameter is described as 'ExtendScript source code to run inside Illustrator.' The tool description adds value beyond the schema by explaining how to produce a return value ('end your script with a bare expression') and providing context about the language (ES3) and the object model. This exceeds the baseline for high schema coverage.

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 clearly states the action ('Executes arbitrary ExtendScript') and the resource (Illustrator's scripting language, 'inside the running Illustrator instance'). It explicitly distinguishes itself from siblings with 'Use this for anything the other tools don't cover directly', making its role as a catch-all tool unambiguous.

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 explicit usage guidance: 'Use this for anything the other tools don't cover directly.' This tells the agent when to choose this tool over sibling tools and implicitly when not to use it (when a specific tool covers the task).

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