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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=false, covering the safety profile. The description adds value by specifying the return contents (row count, kind, column names/types) and the environment requirement, which the annotations do not convey.

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 three short, tightly packed sentences. The primary purpose is front-loaded, and every sentence adds necessary information (what it lists, why to use it, return format, and a prerequisite). No filler or redundant phrases.

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 simple tool with one parameter, an output schema, and annotations covering mutability, the description covers everything needed for correct invocation: its role relative to a sibling, the return content, and an environment requirement. Nothing essential is missing.

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?

The schema covers the single parameter (canvas_id) with a description ('Canvas ID returned by chembl_get_bioactivities (spilled: true)'). The tool description does not add any new meaning beyond the schema, so a baseline score of 3 is appropriate.

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 specific verb (List), a concrete resource (tables and columns staged on a canvas), and the source tool (chembl_get_bioactivities). It also names the sibling chembl_dataframe_query to distinguish this inspection tool from the query tool, making its purpose unmistakable.

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?

It gives explicit usage context: 'inspect before calling chembl_dataframe_query to write correct SQL' and states an environmental prerequisite (CANVAS_PROVIDER_TYPE=duckdb). This tells the agent precisely when to use the tool and what it enables.

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