canvas_open

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

No annotations are provided, so the description carries the burden. It does disclose that the effect is to display the board to a human observer ('beside the chat'), which is genuine behavioral context. It says nothing about whether opening replaces or preserves existing board content, whether a board is created if none exists, or what happens when no human is present (that detail lives only in the schema for 'open').

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 sentences, front-loaded with the primary action, with nothing wasted. The telegraphic phrasing ('Name it with title') is efficient but slightly clipped, which keeps it from a 5.

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 five-parameter, zero-annotation, no-output-schema tool, the description covers the core action but omits the side-effect profile: whether existing drawings are overwritten, whether a missing board is created, and what the caller gets back. The rich schema compensates partially, but the behavioral picture remains incomplete.

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 all five parameters including defaults are documented in structured data; baseline is 3. The description reinforces title (naming) and board (reuse another chat's drawing) but adds no syntax, format, or interaction detail beyond the schema.

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+resource: showing this chat's own whiteboard to the human beside the chat. It also hints at the reuse case via the board parameter. It does not, however, distinguish itself from siblings like canvas_focus or canvas_read, which plausibly also surface the board to a viewer.

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 phrase 'To reuse another chat's drawing (any folder), pass board' gives a condition for one parameter, and 'Name it with title' gives a light instruction. There is no explicit when-to-use-this-vs-an-alternative guidance despite ten canvas siblings, and no statement of when not to call it.

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