get_canvas

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

With no annotations provided, the description carries the full burden. It usefully discloses the output form (official MCP image content) and the nearest-neighbor rendering behavior, but says nothing about prerequisites (an active sprite/document must exist), read-only nature, or failure modes.

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 tight sentences with zero waste, front-loading the core action and output format. Every clause 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?

No output schema exists, but the description compensates by stating it returns MCP image content. However, without annotations it omits prerequisites, read-only confirmation, and error behavior, leaving meaningful gaps for a rendering tool.

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 all four parameters (scale, layerName, frameIndex, checkerboard) are already documented in the schema. The description only echoes the nearest-neighbor scaling concept for the scale param, adding no meaning beyond the schema, so 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 pairs a specific verb ('Renders') with a clear resource ('the active sprite canvas/frame') and states the output format ('PNG image'). It does not explicitly differentiate from close siblings like export_png or get_pixel_grid, but the render-as-image framing is clear.

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 explicit guidance on when to use this versus alternatives such as export_png (file output) or get_pixel_grid (raw pixel data). The distinction is only weakly implied by the phrase 'Returns official MCP image content'.

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