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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint), so the description's additional statement that signing keys are never returned is a genuinely useful data-exposure caveat beyond structured fields. Remaining gaps such as pagination or result ordering are minor for a list tool.

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 short sentences, zero filler, with the operation and its scope front-loaded ahead of the security caveat. Every sentence 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 two-parameter read-only listing with full schema coverage and annotations carrying the safety profile, the description is sufficient to invoke correctly. Without an output schema it could optionally note what an installation record contains, but that omission is minor.

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% – both company and environment are documented, and environment's staging/production enum is enumerated. The description adds no further parameter meaning beyond the phrase 'in this environment', so the baseline 3 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?

States a specific verb (List) and resource (Messenger installations) scoped to an environment, which cleanly separates it from the sibling mutation tools such as summer_messenger_installations_create, _update, and _rotate_key. An agent can identify the operation without opening the schema.

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 by the verb and the environment scoping – read-only inventory of Messenger installations – but there is no explicit when-to-use or when-not-to-use guidance, and no mention of alternatives for related needs (e.g., creating an installation or rotating its key).

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