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

Beyond the annotations, the description discloses a critical silent-failure mode: entering a rate in the wrong currency raises no error and only later causes incorrect revenue and margin. It also tells the agent that the response echoes meta.currency, which is useful behavioral context not present in the schema or annotations.

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 sentences with no filler. It front-loads the core purpose, gives a concrete example, then adds the critical currency warning and response hint. Every sentence 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?

For a simple 3-parameter create tool with no output schema, the description covers the key semantic trap (currency), indicates the response echoes meta.currency, and provides a realistic example. It could be slightly more explicit about the returned object or how this relates to projects_assign_pricing_group, but it is sufficient for correct invocation.

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 coverage is only 33% (only hourly_rate has a description), so the description compensates by clarifying that hourly_rate is a SALES price in the workspace currency. It also helps with project_id and group_name by framing them in the context of creating a billing rate group on a project, though it does not detail their exact formats.

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 begins with a specific verb and resource: 'Create a billing rate group on a project', with a concrete example ('Senior Consultant' at 1450/hour). This clearly distinguishes it from sibling tools like projects_assign_pricing_group, projects_update_pricing_group, and projects_delete_pricing_group.

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 actionable guidance: check the workspace currency before entering a rate because a wrong currency silently produces wrong revenue and margin. It does not explicitly name alternative tools or state when not to use it, but the create semantics and currency precondition provide clear usage context.

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