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

With no annotations, the description carries the behavioral burden. It discloses that the tool performs RAG, returns a synthesized answer rather than raw docs, and includes the raw provider response in _meta. It does not mention limitations or failure modes, but it provides meaningful behavioral context beyond the basic action.

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 and front-loaded, with each sentence earning its place: purpose, usage condition, return behavior, _meta note, and sibling alternative. 'Prefer this before guessing' is slightly vague but adds a useful behavioral nudge without unnecessary length.

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?

For a one-parameter search tool with no output schema and no annotations, it covers the key facts an agent needs: what it searches, when to use it, what it returns, and which sibling to call instead. It doesn't discuss cost, latency, or RAG limitations, but these are minor gaps for this tool type.

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?

The input schema already covers the single query parameter at 100% with detailed guidance about natural language, helpful context, and character limit. The description itself adds no parameter-level semantics, so the baseline of 3 applies.

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 opens with a specific verb and resource: 'Semantic search (RAG) over the Langfuse documentation.' It clearly distinguishes itself from a specific-page lookup by stating it returns 'a concise answer synthesized from relevant docs,' which is a different outcome than fetching a single page.

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?

It explicitly says when to use it: 'Use this whenever the user asks a broader question that cannot be answered by a specific single page.' It also names the alternative: 'If a specific page is needed call getLangfuseDocsPage first,' giving clear routing guidance.

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