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

With no annotations, the description carries the full burden. It implies a read-only operation via 'Get,' but provides no context about error behavior, permissions, or rate limits. It does disclose the core information returned (utilisation, spend breakdown, alert status), which is adequate for a simple getter, but lacks deeper behavioral detail.

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, well-structured sentence that concisely lists the three key data points returned. It is appropriately sized and front-loaded with the verb 'Get,' making it easy to parse.

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?

Without an output schema, the description does a good job of explaining the return content (utilisation, spend breakdown, alert status). It is not overly verbose and covers the essential information for a budget getter. However, it lacks a note about what the tool does NOT do (e.g., historical reports), which would enhance completeness given the 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?

Schema description coverage is 100% with clear descriptions for both parameters (api_key and budget_id). The description adds no additional parameter semantics beyond what the schema already provides, so it meets the baseline for high 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 clearly states the tool's function: 'Get current utilisation, spend breakdown by provider, and alert status for a budget.' It names the resource (budget) and the specific data returned. However, it does not explicitly distinguish itself from sibling tools like get_budget_alerts or department_report, so it lacks the sibling differentiation required for 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?

There is no guidance on when to use this tool versus alternatives. The description only states what it does, without prerequisites, exclusions, or mention of when get_budget_alerts would be more appropriate. This qualifies as 'no guidance.'

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