langfuse-mcp-java

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

The description claims this 'Returns' data (a read operation), but the annotations declare 'destructiveHint: true' and 'readOnlyHint: false', implying data destruction. This is a direct contradiction—fetching a paginated list should not be destructive. The description also fails to explain the 'openWorldHint: true' (external calls) behavior.

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 well-structured with clear sections: purpose definition, trace explanation, response fields, filter behavior, and pagination mechanics. Sentences are purposeful and information-dense. The field list is slightly verbose but necessary given the lack of output schema.

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 lack of output schema, the description comprehensively lists return fields (id, name, userId, sessionId, etc.) and explains the filter/pagination behavior in detail. It adequately covers the 8-parameter complexity despite the schema incorrectly marking all fields as required.

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?

Despite 100% schema coverage, the description adds crucial semantic context: it clarifies that 'All filter parameters are optional' (correcting the schema's erroneous 'required' array), provides the default values for pagination (page=1, limit=20), and explains the paging strategy incrementing page while keeping limit fixed.

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 it 'Returns a paginated list of Langfuse traces' with a specific verb and resource. It adds valuable context by defining what a trace represents ('one end-to-end LLM pipeline execution') and enumerating response fields. However, it misses explicit differentiation from the singular 'fetch_trace' sibling.

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 guidance on filter usage ('Omit any filter you do not need') and pagination strategy ('To page through results, increment page while keeping limit fixed'). However, it lacks explicit comparison to siblings like 'fetch_trace' or 'get_user_traces' to help the agent choose between bulk retrieval and specific lookups.

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