upsert_host_mapping

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

With no annotations, the description carries the full burden. It usefully discloses that writes are immediate and require no second confirmation, which is meaningful for a mutation tool. However, it says nothing about idempotency, required permissions, what happens to omitted fields on update, or the effect of the block action, leaving substantial behavioral gaps.

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 sentences that are front-loaded: the create/update behavior leads, and the immediacy caveat follows. Neither sentence is redundant and there is no filler.

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 six-parameter mutation tool with no annotations and no output schema, the description covers mode selection and write immediacy but omits the map-vs-block semantics, the fact that target is expected for map and omitted for block, and what the call returns. Those gaps are partially compensated by the unusually complete schema, keeping it at an adequate-but-incomplete level.

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%, so the schema already documents all six parameters (id, action, domain, target, comment, enabled) with defaults and constraints. The description adds only the id-presence rule, which the id's own schema description already states ('omit to create a new mapping'). Baseline 3 is appropriate.

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 states a specific verb and resource ('Creates a native DNS Host mapping, or updates one') and explicitly resolves the upsert ambiguity by tying the update branch to the presence of an existing mapping id. The 'Host mapping' resource is distinct from the other upsert siblings (upsert_rewrite_rule, upsert_module), so an agent can place it correctly 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?

It clearly states the condition that selects each mode: omit the id to create, provide an existing mapping id to update. This is real when-to-use guidance for an upsert. It stops short of naming alternatives for related intents (e.g., list_host_mappings to find an id, delete_host_mapping to remove one), so no explicit exclusion guidance is present.

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