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

Annotations already establish that this is a safe, read-only operation, but the description adds meaningful interpretation: billing_ready=false is not an invoice, and a zero conversation limit means unbounded current-policy usage rather than a purchased allowance. These caveats prevent misreading the returned data and go beyond what the structured annotations provide.

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 short and front-loads its core purpose ('Reads Workspace usage and auditable price estimates'). The subsequent sentences each add a distinct interpretive or scope caveat, though the phrasing is somewhat dense and telegraphic.

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?

Because an output schema exists, the description does not need to enumerate return fields, and it instead focuses on interpreting tricky output values such as billing_ready and zero conversation limits. It is complete enough to call and interpret the tool, with the main remaining gap being explicit routing guidance against sibling tools.

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 tool takes zero parameters, so there are no parameter semantics to explain. The baseline for a zero-parameter tool is 4, and the description appropriately does not waste space on nonexistent inputs.

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 uses a specific verb ('Reads') and a clearly scoped resource ('Workspace usage and auditable price estimates'), so the agent knows exactly what data this tool returns. It does not explicitly distinguish itself from siblings like workspace_read or workspace_primary_agent_dashboard, which prevents a 5.

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?

Usage is only implied: the agent can infer this is the tool for usage and price-estimate reads, and the final sentence clarifies that checkout, plan changes, and invoices are out of scope. There is no explicit 'use this when' guidance or named alternative sibling for related queries.

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