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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is covered. The description adds context by explaining the dependency on a prior oecd_query_dataset spill and the duckdb provider requirement, which is useful behavioral context not present in annotations. It does not, however, describe what happens when no spill exists or when the provider condition is unmet, but the output schema covers return shape.

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?

The description is two sentences with no filler. The core purpose is front-loaded, the key usage ordering is stated immediately, and the environment constraint is given last. Every sentence carries distinct and necessary information.

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?

Given the tool has one fully documented parameter, an output schema, and annotations covering read-only and idempotent behavior, the description is complete for agent decision-making. It tells the agent what the tool does, when to call it, what it enables, and the precondition required.

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%: the canvas_id parameter is fully described in the schema, including its 10-character pattern and purpose. The description does not add extra detail about the parameter itself, so the baseline of 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 opens with a specific verb and resource: 'List tables and columns staged on a DataCanvas.' It clearly identifies this as a discovery tool for inspecting spill results, which is distinct from querying via oecd_dataframe_query or fetching dataset metadata. The name and title are supported rather than merely restated.

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?

The description gives explicit sequencing context: 'Call this before oecd_dataframe_query to discover exact table and column names for SQL.' It also states a concrete availability condition: 'Only available when CANVAS_PROVIDER_TYPE=duckdb is set.' It lacks an explicit when-not-to-use statement or mention of alternatives beyond the implied sibling ordering, but the context is clear and actionable.

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