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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds context about organization context requirement and the fallback to active project context, which are useful behavioral traits beyond the schema. It does not contradict annotations and adds meaningful info, though it stops short of describing response structure or error conditions.

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?

Two sentences, no filler. The main action is front-loaded, followed by usage guidance and context requirements. Every word earns its place.

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 single-parameter, read-only list tool with no output schema, the description covers purpose, usage, default behavior, and alternative routing. An agent has everything needed to invoke it correctly without 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 describes projectId fully with 100% coverage, including the default behavior of using active project context. The description repeats this without adding new semantics, so the baseline of 3 for high coverage applies.

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 states a specific verb ('List') and resource ('environments of a project') with added detail ('with variable counts'). It explicitly names the sibling get_environment_variables and distinguishes its scope, so an agent can immediately tell it apart without opening schemas.

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 gives explicit usage guidance: 'Use this to browse a project's environments' and routes to the alternative tool when needed ('for the variables of one use get_environment_variables'). It also notes the requirement for organization context and the default behavior for projectId.

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