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

Annotations already declare non-readonly, destructive, idempotent and closed-world, so the safety profile is covered. The description adds genuinely non-structured context — that this is a partial merge where unspecified fields are preserved — which is the key behavior an agent needs before calling it.

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 waste, with the merge constraint placed immediately after the purpose so the most important behavioral fact is front-loaded.

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 two-optional-parameter settings tool with full annotation coverage and no output schema, this is nearly complete. Minor gaps remain: whether the response returns the resulting settings, and how unknown keys are handled.

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% and both optional parameters (language, timezone) are documented with examples in the schema itself. The description's merge statement reinforces that omitted fields are untouched, but adds no format or validation detail 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?

States a specific verb (update) and resource (user settings), so the agent knows exactly what changes. It does not differentiate itself from the obvious sibling muninn_settings_get, but the mutation intent is unmistakable.

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 only implied: an agent can infer 'call this to change settings' but the description never says when to prefer it, nor points to muninn_settings_get for reading current values first. No exclusions or prerequisites are stated.

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