List PostgreSQL clusters

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

Annotations already declare readOnly, idempotent, non-destructive, and openWorld, so safety is covered. The description adds real behavioral context beyond that: results are constrained by namespace/cluster allowlists and protected clusters are flagged in the output, which tells the agent results may be silently incomplete and that a protection marker should be expected.

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?

Three short sentences, front-loaded with what the resource is before the scoping and filtering caveats. No sentence is redundant; the parenthetical and the allowlist note each carry distinct information.

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?

No output schema exists, but the description compensates by noting allowlist filtering and protected-cluster flagging, which is exactly the return-side nuance an agent needs. Combined with full parameter coverage and rich annotations, nothing material is missing for a list 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?

Schema coverage is 100%, so the baseline is 3. The description goes slightly beyond the schema on `namespace`: the schema only says it defaults to PERCONA_NAMESPACE when set, whereas the description explains that omitting it widens the query to all namespaces - a meaningful semantic the schema does not state. The `context` parameter is left 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 (List) + concrete resource (PerconaPGCluster) with a parenthetical clarifying that this spans PostgreSQL and PgBouncer. The singular/plural contrast with the sibling get_cluster is immediately legible, so an agent can route between them without inspecting 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 an invocation rule ('Omit `namespace` to list across all namespaces'), which is useful, but it never states when to prefer this over get_cluster, list_contexts, or the other list_* siblings. Usage is implied by the verb rather than explicitly scoped, leaving the agent to infer the alternative-selection logic.

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