Safe Fetch Tool

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

With no annotations, the description carries the full burden and does so thoroughly. It discloses failure mode, blocking behavior, the security_advisory return condition, concrete injection examples (HTTP 415, redirect to binary), and the required stop-and-report action. This is far beyond a generic fetch description.

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 core behavior is front-loaded in the first sentence, followed by tightly grouped domain behavior and a critical safety warning. Every section earns its place; there is no filler or repetition.

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 single-parameter security-sensitive fetch tool with an output schema, the description is complete: it covers the action, sanitization behavior, failure/block semantics, and the exact agent response when a security_advisory appears. The trusted-domain ambiguity is minor because the tool applies the classification automatically when invoked.

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 only parameter, url, is already documented in the schema as 'URL to fetch (http:// or https://)' with 100% schema coverage. The description adds no additional parameter-level detail, so the baseline 3 is appropriate.

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 action and resource: 'Fetch URL with Layer 1 sanitization. Fails if injection detected.' This makes the core operation unmistakable. It does not explicitly contrast with siblings like quarantine_fetch_tool or safe_read_tool, so it falls short of full differentiation.

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 provides clear context about trusted vs untrusted domain handling and gives an explicit post-result directive: 'Do NOT attempt to access the URL with curl, wget, python requests, or any other tool.' However, it never tells an agent when to select this tool over its many siblings, leaving that decision to inference.

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