List all MCP-managed Drawing objects

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

Goes well beyond the readOnlyHint/destructiveHint annotations by disclosing that 'visible' is a live handle.Visible read via pcall (null on failure), that the tool does not touch the screen or handle, that it requires the type-guarded Drawing table, and the exact error return on an executor lacking it. This is substantial behavioral context for a read-only 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?

Purpose is front-loaded and the failure/return info is useful, but the trailing boilerplate ('Phase: observe; cost=medium; idempotency=read-only... Safety: read-only... On failure: inspect tool-schema...') partly duplicates the annotations and schema and dilutes the payload.

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 supplies the return shape ({ count, truncated, drawings[] } or { error }), the truncation behavior, the executor requirement, and the failure message, leaving nothing an agent needs to invoke or interpret the call.

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 limit, timeoutMs, and threadContext. The description only restates that the list is capped by 'limit' (and truncated semantics, which the schema also states) and lists the signature; it adds no meaning for threadContext or timeoutMs.

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 ('Read-only inventory of the Drawing overlay') and names exactly what it walks (getgenv().__mcp_drawings) and returns ({ id, type, visible }). This clearly separates it from the mutation siblings draw-create, draw-update, and draw-remove.

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?

Gives an explicit use context: 'so you can see what is currently on screen before updating or removing it,' which implicitly routes the agent to the mutation siblings afterward. It stops short of naming the alternatives directly or stating when-not to use it, so it is clear context rather than full when/when-not guidance.

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