List global env keys

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

Annotations already cover read-only/idempotent/non-destructive, and the description adds genuinely new traits: cost=medium, the active-client prerequisite, bounded-candidates output, and an on-failure recovery path. That is meaningful context beyond the structured hints.

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?

Front-loaded with the purpose, then terse clause-per-fact metadata. Slight redundancy between the signature line and the schema, but no filler prose and everything is scannable.

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 3-optional-param read tool with no output schema and rich annotations, the description covers purpose, prerequisite, cost, and failure handling adequately. Only the absence of alternative-routing guidance keeps it short of complete.

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%, so the schema already documents query, limit, and threadContext with defaults. The description's signature line restates parameter names/types without adding filtering or ranking semantics, so it earns only the baseline.

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?

States a specific verb+resource ('List keys from getgenv/_G') and adds the return preview ('type/value previews'), so the agent knows what it retrieves. It doesn't differentiate itself from nearby siblings like find-global-xrefs or dump-function-env, but the purpose is unambiguous.

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?

Provides contextual markers (Phase: observe; Requires: active-client) that imply when the tool applies, and a failure fallback to tool-schema. However, it never states when to prefer this over alternatives such as find-global-xrefs, so usage selection is left to inference.

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