set_dns_settings

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

Annotations already declare this a non-read-only, idempotent, non-destructive, closed-world mutation, so the safety profile is covered. The description adds a genuine policy constraint (allowlist membership) and hints at a confirm flow, but "Two-phase" never says what phase one does — preview, validation, or error — and never mentions etag-based concurrency.

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 clauses, front-loaded with the action, with zero filler. The terseness edges into under-specification ("Two-phase" as a standalone fragment), but no sentence is wasted.

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 mutation with four parameters at 0% schema description coverage, the definition is too thin. Even with an output schema present, an agent cannot confidently supply `confirm` or `expected_etag`, nor know what the first phase returns, so a correct invocation would likely require trial and error.

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 0%, so the description must carry parameter meaning. It only indirectly touches `servers` (allowlist requirement) and `mode` (via "Manual"); `confirm` and `expected_etag` are entirely unexplained in both schema and description, leaving the most important interaction contract undocumented.

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 concrete verb+resource: "Set WAN DNS." That contrasts implicitly with the get_dns_settings sibling, but the description never names the read counterpart or scopes what 'WAN DNS' covers (servers, mode), so differentiation rests on the verb alone.

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?

A real precondition is given for manual mode (servers must appear in policy.toml's allowlist), which tells the agent when the call will be rejected. But there is no explicit when-to-use vs. alternatives such as apply_desired_state or snapshot_config, and the cryptic "Two-phase" gives no guidance on sequencing.

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