tor_fetch_onion

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

With no annotations provided, the description carries the burden of behavioral disclosure. It does add useful context about the Tor daemon dependency and DNS leak prevention via socks5h, but it omits details on error handling (e.g., what happens if Tor is not running, timeout behavior) and any rate limits. This is adequate but not fully transparent.

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 two sentences, front-loaded with the core action ('Fetch raw HTML'), and every sentence provides essential information (what, how, prerequisite, constraint). There is no waste or redundancy.

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?

This is a simple one-parameter tool with no output schema or nested objects. The description covers the core behavior, prerequisite (Tor daemon), and input constraint, which is largely complete. It could specify failure modes (e.g., if Tor is inaccessible), but given the low complexity, the description is sufficient.

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 schema description of the 'url' parameter already covers its purpose ('.onion URL to fetch (http:// or https://)'). The tool description adds the constraint that only .onion URLs are allowed, but this is implied by the schema and not a significant semantic addition. With 100% schema coverage, a baseline of 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 clearly states a specific action ('Fetch raw HTML') targeting a specific resource ('.onion URL') via a specific mechanism (Tor SOCKS5 proxy). This clearly distinguishes it from sibling tools like tor_scrape_onion and tor_search_onion, which imply different purposes.

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 usage context: it requires a running Tor daemon and only accepts .onion URLs, which tells the agent when this tool is appropriate. However, it does not explicitly contrast with alternatives (e.g., tor_scrape_onion) or mention when not to use it, so it lacks the explicit when-not guidance for a 5.

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