add_arrow

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

Annotations already state idempotentHint=false, destructiveHint=false and openWorldHint=false, so the safety profile is partly covered. The description adds nothing further: it does not say whether the arrow is created on the current scene, whether an id is returned for later move/update_element calls, or how the bound label anchors if the arrow is later moved.

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?

Two short sentences, front-loaded with the core action and with zero filler. It is arguably under-specified rather than verbose, which is the opposite failure mode of conciseness.

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?

An output schema exists, so return values need not be explained, which lowers the burden. However, for a 13-parameter drawing mutation with no annotation coverage of effects and no schema descriptions, the definition leaves the agent guessing about styling parameters and the coordinate system used for the four required values.

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 0% across 13 parameters, so the description carries the full burden and largely fails. It hints that x/y/x2/y2 are the two endpoints and label is midpoint text, but elbowed, opacity, roughness, font_family, strokeColor, strokeStyle, strokeWidth, and font_size are given no meaning at all, and the coordinate space/units of the endpoints are never stated.

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 ("Add an arrow between two points") plus the optional label behavior, so the agent knows exactly what gets created. It does not differentiate itself from the plausible alternatives in the sibling list such as connect or add_rectangle, so it stops short of a 5.

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?

There is no guidance on when to choose this over connect (which likely draws a connective line between elements) or the other add_* shape tools. No prerequisites, no mention of needing an active scene or of what happens if coordinates fall outside the viewport.

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