list_agents

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

Despite the readOnlyHint annotation, the description adds valuable nuance: it explains the exact meaning of installed vs usable, and the concrete pitfall where codex --version exits 0 despite an unwritable home. This goes beyond the annotation's bare safety flag and clarifies what 'can actually run' means.

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?

Every sentence serves a purpose: purpose, field meanings, a critical caveat, and usage direction. It is front-loaded with a clear statement of what the tool does and remains compact despite covering nuanced semantics.

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, the description fully specifies return fields (installed, usable, reason, available) and their semantics, including the installed-but-unusable distinction. The practical guidance to prefer usable completes the picture for choosing an agent.

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 tool accepts zero parameters, so the schema already fully documents the input. The description focuses instead on return fields, which is appropriate; no parameter clarification is needed beyond the empty schema.

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 verb-resource pair ('List the wrapped coding-agent CLIs') and adds scope ('whether each can actually run'), clearly distinguishing it from sibling agent-execution tools like codex/claude. The elaboration about installed vs usable further pins down its function.

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 instructs 'call this first to choose an agent before delegating,' establishing when to invoke it relative to sibling tools. It also advises 'prefer usable' over installed, giving evaluation guidance for interpretation.

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