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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so safety is covered. The description adds real value by disclosing the return surface (status, cost, per-node state, model, result URLs), which is otherwise unavailable since there is no output schema.

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?

One sentence, front-loaded with the action and resource, then the payload; nothing redundant or padded.

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 1-param, no-output-schema read tool the description carries the return-shape burden well, but it omits error/lifecycle context (e.g. what a still-running run looks like, whether to poll after start_run), which an agent would benefit from.

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% and the single run_id is documented as coming 'from a turn or apply_turn'. The description adds nothing further about the identifier's format or origin, so the 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?

States a specific verb+resource ('Read a canvas run') and enumerates the payload (status, cost, node state, model, result URLs), which is more informative than the bare title. It does not, however, distinguish itself explicitly from near-siblings like get_turn, get_generation, or get_cut.

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?

No guidance on when to call this versus get_turn, get_generation, or list_generations, and no mention of polling after start_run/apply_turn. The only flow hint ('run_id from a turn or apply_turn') lives in the schema, not the description.

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