env_facts

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

Annotations declare destructiveHint=true, but the description does not explain any destructive behavior, such as whether adding an existing key overwrites it or if list operations have side effects. It adds example fact types but no behavioral details, leaving the agent without important operational nuance.

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?

The description is two sentences with no filler. The first sentence states the core function, and the second provides a critical boundary with an alternative tool. 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 simple add/list tool, the description plus schema is mostly sufficient. However, the lack of any output schema and the absence of note about overwrite or destructive effects means the agent may wonder what 'list' returns and what 'add' does to an existing key. This is a minor gap for an otherwise simple tool.

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 has 100% description coverage for all 5 parameters, so the baseline is 3. The description's examples ('auth backend, env file locations, local URLs, required env vars') provide useful context for the value parameter, but it does not add param-specific syntax or clarify the relationship between key, value, and context beyond 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?

The description uses specific verbs 'Store and query' and identifies the resource as 'stable environment facts for a project,' making the tool's purpose immediately clear. It also distinguishes itself from the sibling 'cred_refs' tool by explicitly excluding secrets, which differentiates from a likely alternative.

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 explicitly states when not to use the tool ('Not for secrets') and names the alternative ('use cred_refs for that'). This provides a clear exclusion and redirect, which is strong usage guidance. The primary use case is implied by the purpose statement.

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