Create or update a DNS record

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

Annotations already declare idempotentHint=true and destructiveHint=false, and the description is consistent. It adds useful workflow behavior: reads the zone, applies the change, validates with the API, and saves only if validation passes. This is valuable context beyond the annotations, though it doesn't describe failure outcomes in detail.

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 sentences, each earning its place: what it does, the read-validate-save workflow, and the explicit warning against the destructive sibling. Front-loaded and free of 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?

Given an output schema exists and all parameters are documented in the schema, the description covers the essential operational semantics: identity key, validation flow, and alternative routing. A minor gap is unspecified behavior on validation failure, but this is mitigated by the output schema and annotations.

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 reinforces that 'type and host' form the identity key, which helps agents use required parameters correctly, but it doesn't add detail beyond what the schema descriptions already provide.

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 uses specific verbs ('Adds', 'updates') and names the exact resource ('DNS record in a zone') with the matching key ('same type and host'). It clearly distinguishes this from siblings like eurodns_dns_add_records, eurodns_dns_delete_record, and eurodns_dns_save_zone.

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?

Explicitly instructs 'Prefer this over saving a zone directly' and explains why: saving 'replaces the whole zone and drops anything not included.' This gives an agent a clear decision rule between this tool and eurodns_dns_save_zone, plus the add-vs-update condition.

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