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

No annotations, so description carries the burden. It discloses the return (plain text contents) and advises caching-like behavior ('avoid repeated calls'), but doesn't mention error handling or network specifics. Given it's a simple read-only fetch, this is adequate.

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?

Three concise sentences with zero filler. Action is front-loaded, then usage, then return, then caution. Every sentence adds value.

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?

Complete for a no-parameter read tool. It explains what it returns, when to use it, and how it relates to siblings. No output schema needed since return is plain text.

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?

Tool has zero parameters, so baseline 4. The description correctly avoids any param discussion; schema already covers everything.

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?

Clearly states the action: 'Get a high-level, machine-readable index by downloading https://langfuse.com/llms.txt.' It names the specific resource and what it returns, and differentiates from siblings by naming them as follow-up tools.

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?

Explicitly states when to use: 'at the start of a session' and for 'discover key docs endpoints or to seed follow-up calls', names the alternative tools, and warns against repeated calls. Provides clear usage context.

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