fetch_traces

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

With no annotations provided, the description carries the transparency burden. It discloses a key behavioral trait: 'Returns compact metadata (no input/output content).' This hints at read-only semantics (fetch) and avoids the expectation of full trace details. It does not mention auth or rate limits, but given the simple read nature, the disclosure is sufficient for a 4.

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 compact, front-loaded with the main action, and every sentence serves a purpose. It provides essential guidance in three sentences without padding, making it easy to parse quickly.

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?

While the description clarifies the tool's niche among many siblings and notes the response output, it leaves the 10 parameters completely unexplained. An agent would not know how to construct queries (e.g., timestamp formats, allowed order_by values, or filter combinations). Output schema exists, so return values are covered, but parameter usage is a significant gap.

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% and none of the 10 parameters (name, tags, limit, offset, project, user_id, version, order_by, to_timestamp, from_timestamp) are explained in the description. The description adds no meaning to these parameters, failing to compensate for the lack of schema descriptions.

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 starts with a specific verb+resource: 'Fetch traces from Langfuse.' It also explicitly states the response scope ('compact metadata, no input/output content'), distinguishing it from fetch_trace which returns full details. This clearly differentiates from sibling tools like fetch_observations and fetch_sessions.

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 explicit when-to-use and when-not-to-use guidance: 'For analytical questions... use analytics tools instead. For user queries, use list_user_queries. For keyword search, use search_trace_content. Use fetch_trace(trace_id) to get full details.' This names specific alternatives, making selection easy.

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