tools_txt_record_lookupFree public API. Fetch all TXT records on a domain, classifying each as SPF, DKIM, DMARC, BIMI, verification token, or general.
| Name | Required | Description | Default |
|---|---|---|---|
| domain | Yes | Domain to fetch TXT records for. |
| Name | Required | Description | Default |
|---|---|---|---|
| ok | Yes | Always true here; failures return an isError result instead. | |
| data | Yes |
Changes observed during successful MCP inspections.
Output schema / (root)Previous value: -nullNew value: +{
+ "$schema": "http://json-schema.org/draft-07/schema#",
+ "additionalProperties": true,
+ "description": "All TXT records on the domain, classified.",
+ "properties": {
+ "data": {
+ "additionalProperties": true,
+ "properties": {
+ "count": {
+ "type": "number"
+ },
+ "domain": {
+ "type": "string"
+ },
+ "records": {
+ "items": {
+ "additionalProperties": true,
+ "properties": {
+ "category": {
+ "description": "SPF | DMARC | DKIM | Verification | MTA-STS | Other.",
+ "type": "string"
+ },
+ "service": {
+ "description": "For verification tokens, the service that issued it.",
+ "type": "string"
+ },
+ "value": {
+ "type": "string"
+ }
+ },
+ "required": [
+ "value",
+ "category"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ }
+ },
+ "required": [
+ "domain",
+ "count",
+ "records"
+ ],
+ "type": "object"
+ },
+ "ok": {
+ "description": "Always true here; failures return an isError result instead.",
+ "type": "boolean"
+ }
+ },
+ "required": [
+ "ok",
+ "data"
+ ],
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is fully covered. The description adds one genuinely useful behavioral fact ('Free public API' implies no auth needed), but says nothing about rate limits, caching, or failure behavior on NXDOMAIN/no-records.
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 tight sentences with the core action front-loaded and no redundancy. 'Free public API' is marginally promotional but still carries actionable information (no key required).
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 single-parameter read tool with an output schema and rich annotations, the description covers what it does and what it returns well enough to invoke correctly. Only edge-case behavior and comparison with the dedicated SPF/DKIM/DMARC checkers is missing.
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?
One parameter with 100% schema description coverage, so the schema already defines 'domain'. The description adds no format guidance (apex vs subdomain, wildcard, IDN) beyond what the schema provides — the baseline of 3 applies.
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 and resource ('Fetch all TXT records on a domain') plus the classification it performs. The scope word 'all' implicitly separates it from the single-purpose siblings (spf_record_checker, dmarc_record_checker, dkim_record_checker), but no sibling is named, so differentiation is left to inference.
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 never says when to use this tool versus the many per-record checkers in the sibling list, nor does it state prerequisites or exclusions. 'Free public API' is context about cost/auth, not usage guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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