Paint: live preview page

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

Annotations already cover the safety profile (non-destructive, idempotent, open-world), so the description only needs to add context — and it does: it discloses that only 127.0.0.1 is bound (a real security-relevant constraint), that repaint cadence is once per second, and that status returns the URL. It does not say what happens on a port collision or on stopping an already-stopped server, so it falls short of a 5.

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, zero filler, and the core purpose is front-loaded ahead of the binding and status details. Every clause carries information an agent or human caller needs.

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 two-parameter, non-destructive tool with no output schema, the description covers purpose, network scope, behavior cadence, and the status return adequately. Missing pieces (port-conflict behavior, whether a canvas must be open) are minor rather than blocking.

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 50%: the port parameter carries its own default documentation ('Default 4173, or --serve at startup') while the action enum has no schema description. The description partially compensates by explaining what 'status' returns, but says nothing about start/stop semantics or the interaction between action and port, so it adds only marginal value over 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?

The description states a concrete verb pair and resource: it starts/stops a localhost page that renders every open canvas at ~1 fps. That is far more specific than the name alone. It does not, however, differentiate itself from the sibling paint_preview, which an agent could easily confuse with a live-serving tool.

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?

Usage is only implied: the mention that action:'status' reports the URL hints at the monitoring use case, and 'so a human can watch the drawing happen' implies the when. There is no explicit statement of when to pick this over paint_preview or paint_inspect, and no stated prerequisite that a canvas must already exist.

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