beel_get_usage

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

Annotations already mark this as read-only, idempotent, and non-destructive. The description adds valuable behavioral context beyond that: the billable unit count includes empty and unclaimed accounts, the 404 error for non-own account IDs, and the required `manage_accounts` entitlement. This gives the agent a full picture of what will happen and what is needed, well beyond the annotation hints.

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 cohesive paragraph, front-loaded with the core purpose. It then explains the billable-unit nuance, the ownership requirement, the entitlement, and the endpoint. No wasted words, and each sentence earns its place, though it could be slightly tightened by removing the endpoint line (which is redundant with other metadata). Still, it is well-structured and easy to scan.

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 tool with one parameter and no output schema, the description covers all necessary context: what it returns, the parameter semantics, error behavior, authentication requirement, and even the underlying endpoint. Nothing an agent needs to decide whether to call it and how to call it correctly is missing. The only theoretical gap (response format) is acceptable given no output schema is provided.

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 100% (account_id described as 'Your own account id.'), so the schema already documents the parameter. The description enriches this by explaining why it must be the caller's own account (usage is a property of the provisioner) and that other IDs yield 404. It adds meaning beyond the schema without over-explaining.

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 precise action and resource: 'Returns how many accounts you have provisioned and the billable count that follows from them.' It clearly distinguishes this from list/get account tools by focusing on usage/billing, and even clarifies the billable unit. An agent understands exactly what this tool computes versus siblings like beel_get_account.

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 implicitly conveys usage context: it is for retrieving usage/billing numbers, and explicitly warns that account_id must be the caller's own account (any other id returns 404). However, it does not name alternative tools or state when not to use this tool, such as 'use list_accounts to enumerate accounts instead'. That explicit exclusion is missing.

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