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

With no annotations, the description carries the full behavioral burden and meets it: it discloses the return shape, the separate signature/proof parts, the 8 KiB lane size constraint, and the local verification requirement. It also surfaces the privacy motivation for routing through a private lane.

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 dense but every sentence earns its place: return value, part semantics, size constraint, verification guidance, and privacy routing. The key return-value information is front-loaded in the first sentence.

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 fetch-style tool without an output schema, this description is remarkably complete: it names the return object, explains the parts, gives verification steps, and documents the privacy-sensitive alternative. The agent has enough context to invoke the tool correctly and handle privacy tradeoffs.

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 already documents both parameters with 100% coverage, so the baseline is 3. The description adds meaningful extra context by explaining why part=sig and part=proof exist and why they must be separate, going beyond the schema text.

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 what the tool does: it fetches a pseudonymous channel descriptor by handle, and even shows the return shape. It distinguishes itself from a direct directory lookup by stressing the private-lane requirement, which helps an agent pick it apart from siblings like null_void_directory.

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 tells the agent when to avoid the direct path and use the stdio door, explaining the privacy reason. It also instructs that all three parts must be verified locally before following the descriptor, and explains how the part parameter is used.

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