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

Annotations already declare readOnlyHint=true, so the read-only nature is covered. The description adds functional context: it lists both standard and custom objects, includes fields, and mentions the underlying REST endpoint. This goes beyond the annotation by explaining the scope and output focus, though it doesn't detail pagination or response format.

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 sentences with no fluff. The first sentence states the action and scope, the second gives the use case and an endpoint reference. Every word earns its place.

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?

With no output schema, the description indicates the return content ('objects (standard + custom) and their fields'). Given zero parameters and a simple list operation, this is adequate. The REST endpoint adds an extra anchor for agents familiar with Twenty's API. Minor gap: no mention of response format or potential pagination, but complexity is low.

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?

Tool has zero parameters, so the baseline is 4. The description appropriately notes that it lists everything ('all objects') and includes the REST endpoint, which is sufficient context for a parameterless operation.

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?

Description uses a specific verb 'List' and clearly identifies the resource: 'all objects (standard + custom) and their fields from the Twenty schema'. This distinguishes it from sibling list tools that target specific record types (companies, people, etc.) by focusing on metadata schema objects.

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?

Explicitly states when to use: 'use this to discover custom objects/fields and valid field names'. This gives clear context for schema discovery. It doesn't explicitly exclude alternatives, but the sibling tools are clearly for record listing, so the intended usage is clear.

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