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

Annotations are absent, so the description bears full responsibility for disclosing behavioral traits. It does not mention whether the operation is read-only, what side effects (if any) occur, or how errors are handled. The description only states what the tool represents, not how it behaves when invoked.

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 short, direct, and front-loaded with the primary purpose ('directory of your agents'). It includes relevant extra detail about address formats without unnecessary fluff. No redundant or tangential information is present.

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?

With no output schema and no annotations, the description must convey what the tool returns. It mentions attributes like address, harness, machine, and status, but does not explicitly state whether the output is a list of agents, a single agent, or something else. Given the likely simple nature, it is moderately complete but leaves some ambiguity.

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 provides a description for the 'query' parameter ('optional substring filter'), giving high coverage. However, the tool description adds no extra detail about how the query interacts with the directory (e.g., which fields are searched). It remains minimal, so the 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 that the tool is a directory of agents, listing key attributes like address, harness, machine, and status. This uniquely identifies its purpose and distinguishes it from sibling tools such as bus_send or bus_reply.

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 does not provide guidance on when to use this tool compared to alternatives. While it is implicitly a listing/directory tool, there is no explicit instruction like 'use this to view agents' or 'instead of bus_check'. Sibling tools vary in function, so without explicit usage context, an agent may not know which tool to pick.

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