list_environments

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely new context: each listed environment carries its own read-only and role policy, which tells the agent this call doubles as a permissions probe before attempting writes.

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 dense sentence with the resource and scope front-loaded and zero filler. It is compact, though the parenthetical example list and policy clause pack in enough that it borders on compressed rather than structured.

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?

There is no output schema, so the description carries the burden of signaling return content, and it does so by naming both the environment identifiers and the per-environment read-only/role policy. The remaining gap is the optional filter parameter's effect, which the schema covers but the description does not reinforce.

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?

Schema description coverage is 100% and there is only one optional parameter, which itself documents the allowed values and the omit-for-default behavior. The description contributes nothing about the environment filter and arguably reads as if it always lists all environments, leaving the filtering behavior entirely to the 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?

Specific verb+resource ("List the named z/OS environments") with concrete examples (DEV/TEST/UAT/PROD, LPARs) and a stated scope ("this server can reach"). No sibling tool overlaps this discovery role, so explicit differentiation is less critical, but the description never turns that absence into an explicit positioning statement.

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?

Usage is implied rather than stated: the description tells you it enumerates reachable environments and their policies, which suggests calling it before targeting an environment, and the schema cross-references "see list_environments" in other tools' params. It never says when not to call it or what to do with the result, and does not explain the interaction with its own optional environment filter.

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