Email posture for any domain: can it receive mail, can it be spoofed? MX, SPF and DMARC.
Full email posture for a domain: can it receive mail, and can it be spoofed?
Runs MX, SPF and DMARC lookups together and returns a plain-language verdict alongside the raw records: can_receive_mail, spoofable, and a list of specific findings. Use this as the default check before emailing an unfamiliar domain, when judging whether inbound mail claiming to be from a domain could be forged, or when auditing your own domains. Prefer this over the single-record tools unless you already know which record you need.
| Name | Required | Description | Default |
|---|---|---|---|
| domain | Yes | Domain to check, e.g. "example.com". A full email address is accepted and the domain is taken from it. |
| Name | Required | Description |
|---|---|---|
| mx | No | |
| spf | No | |
| dmarc | No | |
| domain | Yes | |
| summary | Yes | Plain-language verdict. |
| findings | No | One line per specific problem; empty when the domain is correctly configured. |
| spoofable | Yes | True unless DMARC is present AND at an enforcing policy. Deliberately conservative: without enforcement a receiver has no instruction to reject forged mail, however good the SPF record is. |
| checked_at | No | |
| can_receive_mail | Yes | False when the domain publishes no MX records. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so the read-only nature is covered. The description adds value by disclosing that the tool runs three lookups together, returns a verdict plus raw records, and produces specific fields (can_receive_mail, spoofable, findings). This enriches the agent's understanding beyond the annotations without contradicting them.
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?
The description is tightly structured: a one-line outcome summary, a sentence on mechanics and output, and two sentences on usage context. Every sentence adds information; there is no filler or repetition of schema or annotation content.
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-only, output-schema-bearing tool, the description covers what it does, how it behaves, when to use it, and how it relates to sibling tools. The output schema handles return-value details, so nothing needed for correct invocation 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?
Schema coverage is 100%, and the schema's parameter description already explains that a domain is required and that a full email address is accepted with the domain extracted. The tool description adds no additional parameter-specific meaning, so 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?
The description opens with a specific, outcome-focused statement: 'Full email posture for a domain: can it receive mail, and can it be spoofed?' It then names the exact operations (MX, SPF, DMARC lookups) and explicitly contrasts itself with the sibling single-record tools, so an agent can distinguish it immediately.
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 gives explicit guidance: 'Use this as the default check before emailing an unfamiliar domain, when judging whether inbound mail claiming to be from a domain could be forged, or when auditing your own domains.' It also states when not to use it: 'Prefer this over the single-record tools unless you already know which record you need.' This leaves no ambiguity about selection.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
DMARC record, policy, and whether it actually protects.
Returns the DMARC TXT record at _dmarc., its policy (none / quarantine / reject), the percentage it applies to, and whether that policy protects against spoofing. Also flags the case of MULTIPLE DMARC records, which RFC 7489 requires receivers to treat as no policy at all — a domain in that state is unprotected however strict its records look. A policy of "none" is monitoring only and does not stop forged mail. Use when assessing whether mail claiming to be from a domain can be trusted.
| Name | Required | Description | Default |
|---|---|---|---|
| domain | Yes | Domain to check, e.g. "example.com". A full email address is accepted and the domain is taken from it. |
| Name | Required | Description |
|---|---|---|
| found | No | |
| domain | Yes | |
| policy | No | "ignored" means duplicate records cancelled the policy out. |
| record | No | |
| meaning | No | |
| percent | No | The pct= tag; defaults to 100. |
| protects | No | False for p=none (monitoring only) and for duplicate records. |
| all_records | No | Present only when more than one DMARC record exists. |
| multiple_records | No | RFC 7489 requires receivers to apply NO policy when more than one record exists. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the readOnlyHint and idempotentHint annotations, the description adds nuanced behavior: the interpretation of multiple DMARC records as no policy, the distinction of 'none' as monitoring-only, and the actual protection assessment. These details materially help an agent reason about results.
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?
The description is front-loaded with the core answer, then adds important caveats. Every sentence earns its place; there is no filler. The length is justified by the valuable edge-case explanations.
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?
With an output schema present, the description need not detail return formatting. It covers the purpose, the edge cases, and the usage context, making it complete for an agent to invoke correctly. No gaps.
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 covers 100% of the single parameter, including the acceptance of a full email address. The tool description adds no additional parameter semantics beyond what the schema already provides, so the baseline of 3 is warranted.
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?
Description states a specific verb (returns), resource (DMARC record) and scope (policy, percentage, protection). It distinguishes from siblings like get_spf_record and get_mx_records by focusing on DMARC-specific details. The purpose 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?
Explicitly states when to use: 'Use when assessing whether mail claiming to be from a domain can be trusted.' It also clarifies the implications of a 'none' policy and the multiple-record edge case, giving the agent clear context. Does not explicitly contrast with siblings, but the usage guidance is direct.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Mail exchanger records for a domain.
Returns the MX hosts in priority order and whether any exist. A domain with no MX records cannot receive mail, so sending to it will bounce. Use when you only need deliverability and not spoofing posture; use check_email_domain for the full picture.
| Name | Required | Description | Default |
|---|---|---|---|
| domain | Yes | Domain to check, e.g. "example.com". A full email address is accepted and the domain is taken from it. |
| Name | Required | Description |
|---|---|---|
| found | No | Whether any MX record exists. |
| hosts | No | MX hosts, lowest priority first. |
| domain | Yes | |
| can_receive_mail | No |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, so the safety profile is clear. The description adds useful behavioral context beyond the annotations: it returns records in priority order, indicates whether any MX records exist, and explains the real-world consequence of no records (mail bounces). No contradiction with annotations.
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?
The description is tightly packed into three sentences with no filler: the core behavior, a key consequence, and routing guidance. It front-loads the primary purpose and stays well within a readable size.
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?
With an output schema available, the description does not need to explain return values in detail. It already mentions ordering and existence, adds the bounce implication, and points to the alternative for broader checks. For a single-parameter read-only tool, nothing essential 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?
The input schema fully documents the only parameter, 'domain', including an example and the note that an email address is accepted. The description itself adds no parameters, but that is acceptable because the schema coverage is 100%, so the baseline 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?
The description uses a specific verb-object pair: 'Returns the MX hosts in priority order and whether any exist.' It clearly identifies the resource (mail exchanger records for a domain) and distinguishes itself from check_email_domain by stating it covers deliverability rather than spoofing posture.
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 explicitly tells the agent when to use this tool ('Use when you only need deliverability') and when to consider the alternative ('use check_email_domain for the full picture'). This is direct, actionable guidance that resolves routing ambiguity.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
SPF record and how strict it is.
Returns the SPF TXT record, the qualifier on its all mechanism (fail / softfail / neutral / pass) and what that means in practice, plus whether more than one SPF record exists — which receivers treat as an error, leaving the domain unprotected. Use when diagnosing why mail from a domain is being rejected or marked.
| Name | Required | Description | Default |
|---|---|---|---|
| domain | Yes | Domain to check, e.g. "example.com". A full email address is accepted and the domain is taken from it. |
| Name | Required | Description |
|---|---|---|
| found | No | |
| domain | Yes | |
| record | No | The raw SPF TXT record, or null when absent. |
| strict | No | True only for `-all`, the one strict answer. |
| meaning | No | What the qualifier means in practice. |
| qualifier | No | The qualifier on the `all` mechanism. |
| multiple_records | No | More than one SPF record: receivers treat this as permerror, so SPF effectively fails. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is covered. The description adds non-obvious behavioral context—specifically that multiple SPF records cause receivers to treat the domain as unprotected—which enriches the agent's understanding beyond a simple read operation.
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?
At roughly 65 words, the description is reasonably tight and front-loads the core purpose ('SPF record and how strict it is') before explaining the return values and usage. The opening fragment is slightly informal and could be trimmed, but overall every sentence earns its place.
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 the low complexity (one parameter, read-only lookup) and the existence of an output schema, the description is thorough. It covers the purpose, key return values, an error condition, and the primary use case. No critical behavioral detail is missing for an agent to call this correctly.
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% with a well-documented `domain` parameter, including a helpful note that a full email address is accepted. The description adds no parameter-specific detail beyond the schema, so a baseline of 3 is appropriate since the schema carries the load.
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 ('Returns') with a clear resource (SPF TXT record, `all` qualifier, multi-record status). It clearly differentiates from siblings like get_dmarc_record and get_mx_records by focusing specifically on SPF semantics and its strictness qualifier, so an agent can tell them apart without opening schemas.
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 says 'Use when diagnosing why mail from a domain is being rejected or marked,' giving clear context for invocation. It stops short of naming sibling alternatives and when NOT to use this tool, but the usage context is concrete and actionable.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Recent tool additions, removals, and schema changes observed during successful MCP inspections. Dates show when Glama detected each change.
check_email_domain1 field changedOutput schema / (root)Previous value: -nullNew value: +{
+ "properties": {
+ "can_receive_mail": {
+ "description": "False when the domain publishes no MX records.",
+ "type": "boolean"
+ },
+ "checked_at": {
+ "format": "date-time",
+ "type": "string"
+ },
+ "dmarc": {
+ "properties": {
+ "all_records": {
+ "description": "Present only when more than one DMARC record exists.",
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ },
+ "found": {
+ "type": "boolean"
+ },
+ "meaning": {
+ "type": "string"
+ },
+ "multiple_records": {
+ "description": "RFC 7489 requires receivers to apply NO policy when more than one record exists.",
+ "type": "boolean"
+ },
+ "percent": {
+ "description": "The pct= tag; defaults to 100.",
+ "type": "integer"
+ },
+ "policy": {
+ "description": "\"ignored\" means duplicate records cancelled the policy out.",
+ "enum": [
+ "none",
+ "quarantine",
+ "reject",
+ "ignored",
+ "unspecified"
+ ],
+ "type": "string"
+ },
+ "protects": {
+ "description": "False for p=none (monitoring only) and for duplicate records.",
+ "type": "boolean"
+ },
+ "record": {
+ "type": "string"
+ }
+ },
+ "type": "object"
+ },
+ "domain": {
+ "type": "string"
+ },
+ "findings": {
+ "description": "One line per specific problem; empty when the domain is correctly configured.",
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ },
+ "mx": {
+ "properties": {
+ "found": {
+ "description": "Whether any MX record exists.",
+ "type": "boolean"
+ },
+ "hosts": {
+ "description": "MX hosts, lowest priority first.",
+ "items": {
+ "properties": {
+ "host": {
+ "description": "Mail exchanger hostname.",
+ "type": "string"
+ },
+ "priority": {
+ "description": "Lower is preferred.",
+ "type": "integer"
+ }
+ },
+ "type": "object"
+ },
+ "type": "array"
+ }
+ },
+ "type": "object"
+ },
+ "spf": {
+ "properties": {
+ "found": {
+ "type": "boolean"
+ },
+ "meaning": {
+ "description": "What the qualifier means in practice.",
+ "type": "string"
+ },
+ "multiple_records": {
+ "description": "More than one SPF record: receivers treat this as permerror, so SPF effectively fails.",
+ "type": "boolean"
+ },
+ "qualifier": {
+ "description": "The qualifier on the `all` mechanism.",
+ "enum": [
+ "fail",
+ "softfail",
+ "neutral",
+ "pass",
+ "unspecified"
+ ],
+ "type": "string"
+ },
+ "record": {
+ "description": "The raw SPF TXT record, or null when absent.",
+ "type": "string"
+ },
+ "strict": {
+ "description": "True only for `-all`, the one strict answer.",
+ "type": "boolean"
+ }
+ },
+ "type": "object"
+ },
+ "spoofable": {
+ "description": "True unless DMARC is present AND at an enforcing policy. Deliberately conservative: without enforcement a receiver has no instruction to reject forged mail, however good the SPF record is.",
+ "type": "boolean"
+ },
+ "summary": {
+ "description": "Plain-language verdict.",
+ "type": "string"
+ }
+ },
+ "required": [
+ "domain",
+ "can_receive_mail",
+ "spoofable",
+ "summary"
+ ],
+ "type": "object"
+}get_dmarc_record1 field changedOutput schema / (root)Previous value: -nullNew value: +{
+ "properties": {
+ "all_records": {
+ "description": "Present only when more than one DMARC record exists.",
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ },
+ "domain": {
+ "type": "string"
+ },
+ "found": {
+ "type": "boolean"
+ },
+ "meaning": {
+ "type": "string"
+ },
+ "multiple_records": {
+ "description": "RFC 7489 requires receivers to apply NO policy when more than one record exists.",
+ "type": "boolean"
+ },
+ "percent": {
+ "description": "The pct= tag; defaults to 100.",
+ "type": "integer"
+ },
+ "policy": {
+ "description": "\"ignored\" means duplicate records cancelled the policy out.",
+ "enum": [
+ "none",
+ "quarantine",
+ "reject",
+ "ignored",
+ "unspecified"
+ ],
+ "type": "string"
+ },
+ "protects": {
+ "description": "False for p=none (monitoring only) and for duplicate records.",
+ "type": "boolean"
+ },
+ "record": {
+ "type": "string"
+ }
+ },
+ "required": [
+ "domain"
+ ],
+ "type": "object"
+}get_mx_records1 field changedOutput schema / (root)Previous value: -nullNew value: +{
+ "properties": {
+ "can_receive_mail": {
+ "type": "boolean"
+ },
+ "domain": {
+ "type": "string"
+ },
+ "found": {
+ "description": "Whether any MX record exists.",
+ "type": "boolean"
+ },
+ "hosts": {
+ "description": "MX hosts, lowest priority first.",
+ "items": {
+ "properties": {
+ "host": {
+ "description": "Mail exchanger hostname.",
+ "type": "string"
+ },
+ "priority": {
+ "description": "Lower is preferred.",
+ "type": "integer"
+ }
+ },
+ "type": "object"
+ },
+ "type": "array"
+ }
+ },
+ "required": [
+ "domain"
+ ],
+ "type": "object"
+}get_spf_record1 field changedOutput schema / (root)Previous value: -nullNew value: +{
+ "properties": {
+ "domain": {
+ "type": "string"
+ },
+ "found": {
+ "type": "boolean"
+ },
+ "meaning": {
+ "description": "What the qualifier means in practice.",
+ "type": "string"
+ },
+ "multiple_records": {
+ "description": "More than one SPF record: receivers treat this as permerror, so SPF effectively fails.",
+ "type": "boolean"
+ },
+ "qualifier": {
+ "description": "The qualifier on the `all` mechanism.",
+ "enum": [
+ "fail",
+ "softfail",
+ "neutral",
+ "pass",
+ "unspecified"
+ ],
+ "type": "string"
+ },
+ "record": {
+ "description": "The raw SPF TXT record, or null when absent.",
+ "type": "string"
+ },
+ "strict": {
+ "description": "True only for `-all`, the one strict answer.",
+ "type": "boolean"
+ }
+ },
+ "required": [
+ "domain"
+ ],
+ "type": "object"
+}check_email_domainget_dmarc_recordget_mx_recordsget_spf_recordClaiming proves that you control a remote MCP connector. It does not move, proxy, or interrupt the server.
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Check if a domain can be email-spoofed: SPF, DMARC, DKIM, MX graded from public DNS. Authless.
Email-domain intelligence: MX capability, provider, disposable status, SPF, DMARC, and MTA-STS.
Monitor and manage email authentication (SPF, DKIM, DMARC, MTA-STS, BIMI) for your domains.
Check email deliverability for a domain: MX, SPF, DKIM, DMARC, blacklists. Graded, no key.
Add one secure layer between your agents and this server.
check_email_domain is the comprehensive composite, while get_dmarc_record, get_mx_records, and get_spf_record target distinct record types. However, check_email_domain overlaps somewhat with each of the single-record tools, though the descriptions clearly state when to use each.
Three tools follow the get_<record>_records pattern, and one uses check_<noun>_domain. The verbs are consistent (check/get) and the object is always a domain-related resource, making the naming clear. The slight variation in verb (check vs get) is minor and justified by the composite nature.
Four tools cover the domain email checking domain well: a composite plus the three constituent lookups. This is a tight, purposeful set without redundancy or bloat, appropriate for a focused MCP server.
The set covers MX, SPF, DMARC, and a combined check, which is comprehensive for email posture. There is no tool for DKIM or other email authentication records, but DKIM is less commonly checked and the existing tools provide a thorough overview. Missing a tool to check for other SPF-like mechanisms (e.g., TXT related) is minor.
