Fetch Working Example

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

Annotations already include readOnlyHint=true and idempotentHint=true, and the description reinforces them by stating 'does not execute the example.' It also adds valuable non-obvious context: the paid cost ($0.001 USDC or 1000 drops XRP) and the matched=false response semantics, which go beyond what annotations provide.

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?

Two tight sentences front-load what the tool fetches, then cover usage context, fallback behavior, and cost. No filler or redundant restatement of schema details; every clause earns its place.

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 4-parameter fetch tool with an output schema, the description fully equips an agent: what it returns (filename, install/run, source), when to choose it, what happens when no example matches, cost, and non-execution guarantee. Nothing needed to invoke it correctly is missing.

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 100%, so the schema already documents all four parameters. The description adds some helpful context with goal examples ('agent, rag, chat, payment, rlusd') but does not add meaning beyond what the schema provides for runtime, language, or framework.

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?

States a specific verb and resource: 'Fetch one complete runnable file' with concrete goal examples (agent, rag, chat, payment, rlusd). Explicitly names its sibling fetch_latest_syntax and explains the distinction, making it easy for an agent to select this tool over alternatives.

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?

Directly says when to use this tool: 'Use when fetch_latest_syntax snippets are too small to execute.' It also provides the fallback behavior ('matched=false means no catalog example — then fetch_latest_syntax'), giving explicit when-to-use and when-not-to-use guidance.

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