estimate_costs

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 the source field, grouping options, and output structure, which is helpful. But it lacks details on parameter interactions, default behavior, or edge cases, leaving some behavioral ambiguity.

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 concise, front-loaded with the primary purpose, and uses three short sentences to convey the main functionality, grouping options, and return values. No wasted words.

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?

Given the tool's complexity (7 optional parameters) and lack of annotations, the description is only partially complete. It states return values but does not explain how filters, time ranges, or grouping interact. The existence of an output schema helps, but the description still leaves gaps.

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 compensate. It explains possible values for group_by and bucket_by, but leaves tags, project, start_date, end_date, and time_range entirely unexplained. This is insufficient for the tool's 7 parameters.

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 computes a cost breakdown from the Langfuse totalCost field. It distinguishes itself from sibling analytics tools by focusing specifically on cost, and mentions grouping options and return values, making the purpose fully explicit.

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 provides clear context for when to use the tool (when a cost breakdown is needed) and explains grouping capabilities. However, it does not explicitly mention alternatives or exclusions, so it falls just short of a perfect score.

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