list_custom_fields

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

Annotations declare readOnlyHint=true, so the agent knows this is a safe read operation. The description adds valuable behavioral context: the tool supports pagination (page_size) and the recommended caching strategy to reduce redundant requests. It doesn't mention rate limits or return format, but the caching guidance is a meaningful behavioral disclosure beyond the annotation.

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 a single sentence followed by a clear, actionable usage note. It's concise and front-loads the core purpose ('List all custom fields') before the caching guidance. The guidance is somewhat long but earns its place by providing critical usage strategy. No wasted words.

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 read-only list tool with no output schema, the description covers the essential context: what it does, how to use it efficiently, and the caching strategy. It doesn't describe the return format or the filtering parameters, but the caching guidance is the most important operational detail. Given the tool's simplicity and the readOnlyHint annotation, this is nearly complete.

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 only 29%, so the description should compensate for the undocumented parameters. The description mentions page_size and implies pagination, but it doesn't explain the filtering parameters (name__iexact, name__icontains, etc.) or ordering. The caching guidance adds context for page_size but leaves the other parameters unexplained. Baseline 3 is appropriate because the description adds some value but doesn't fully compensate for the low coverage.

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 clear verb and resource: 'List all custom fields.' It distinguishes itself from related tools like get_custom_field (singular) and delete_custom_field by focusing on listing all fields. However, it doesn't explicitly name sibling alternatives, so it doesn't fully differentiate from other list_* tools, though the resource is unambiguous.

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 provides explicit usage guidance: fetch all custom fields up front with a large page_size, cache them for the session, and search locally for matches by name before making further API calls. This tells the agent when and how to use the tool, and implicitly when not to (avoid repeated API calls). This is strong, actionable guidance.

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