list_agents

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

Without annotations the description carries the full burden; it signals read-only behavior ('list diagnostics') and an unscoped sweep ('every known session'), and flags the tool as legacy, which is useful deprecation context. However it says nothing about cost, permissions, or why the legacy path differs from the current one.

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?

A single efficient sentence with the deprecation signal front-loaded where an agent will see it first. Nothing is padded, though the terseness contributes to the ambiguity noted elsewhere.

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?

An output schema covers return values, but the description never resolves the agents-vs-sessions mismatch, never explains what 'diagnostics' contains, and gives no guidance on whether a legacy tool should be preferred over get_agent_status. For an agent deciding whether to call this at all, that is a real gap.

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 takes zero parameters, so the schema-completeness burden on the description is minimal. With no parameters there is nothing to clarify, and the description correctly implies no output filtering is possible.

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 names a verb and a resource ('list diagnostics ... for every known session'), but the resource conflicts with the tool name 'list_agents'. With agent-focused siblings like get_agent_status and list_pending_actions, the agent/session ambiguity makes it unclear what this actually enumerates.

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?

'Legacy helper' implies deprecation and that a preferred alternative exists, but the description never names that alternative or states when this should still be used. No conditions, exclusions, or sibling routing are provided.

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