evaluate_budget

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

With no annotations provided, the description carries the full burden. It discloses that the tool never raises exceptions and that an empty ledger yields total_spent_usd=0.0 and within_budget=True, which is valuable non-obvious behavior. However, it does not discuss other potential behaviors like rounding or timezone handling, so a 4 is appropriate.

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 two sentences with no redundant words. The first sentence states the core operation, and the second adds a critical edge-case behavior. It is well-structured and front-loaded, earning a 5.

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?

The tool is simple with two parameters and an output schema. The description covers the operation and a key edge case. Since an output schema exists, it need not describe return values in detail. However, it lacks explicit usage context (when to use vs. alternatives), which is a minor gap. Thus a 4.

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 0%, so the description must explain parameters. It does explain that window_days is a time window and limit_usd is a comparison threshold, adding meaning beyond the bare schema. It does not specify units or constraints beyond what the schema already provides (e.g., default for window_days). Given the partial explanation, a 4 is suitable.

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 'Sum' and identifies the resources 'spend_intent amounts' and 'limit_usd', making the tool's function unambiguous. It clearly differs from sibling tools such as record_spend_intent (which records) and classify_action (which classifies), so it earns 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?

The description does not explicitly state when to use this tool versus alternatives, nor does it mention exclusions or prerequisites. It only implies usage for budget evaluation, so it receives a 3 for implied usage rather than explicit guidance.

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