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

Annotations already declare read-only, idempotent, non-destructive behavior. The description adds meaningful output context for a special case: private selectors are opaque private: refs with no provider IDs. It does not describe general return shape, error behavior, or what 'current controls' concretely includes.

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 tightly written sentences with no filler. The primary operation is front-loaded, and the conditional project_id detail follows immediately.

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?

There is no output schema and 0% schema description coverage, yet the description omits the 'values' parameter and does not explain the return structure or what 'Canvas controls' entail. For a tool with a nested object parameter among many canvas siblings, this leaves significant gaps for an agent to call it correctly.

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%, so the description must compensate. It implies model_key via 'live model' and explains project_id's effect, but it completely ignores the 'values' parameter, which is a nested object. Two of three parameters are only partially addressed and one is undocumented.

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: 'Read current Canvas controls for a live model.' An agent can understand the core operation. However, it does not explicitly differentiate itself from siblings like canvas_read, canvas_read_node, or canvas_find_models.

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?

Provides conditional guidance for project-owned ElevenLabs voices (pass project_id), which implies when the parameter matters. But it gives no explicit when-to-use vs alternatives, no exclusions, and no guidance on when not to use project_id.

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