BlackVeil DNS & Email Security Scanner

check_agent_discovery

Read-onlyIdempotent

Assess IETF BANDAID agent-discovery DNS records: finds SVCB agent records under _agents, reports whether the discovery zone is DNSSEC-anchored (unsigned means spoofable endpoints), evaluates DANE/TLSA binding trust and checks capability-document integrity (cap / cap-sha256). Read-only; uses Private-Use SVCB param code points pending IANA assignment.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "domain": "<domain>"
    },
    "name": "check_agent_discovery"
  }
}

Input Schema

Name	Required	Description
`name`	No	Resolve a single named agent ({name}.{domain}) instead of enumerating the zone.
`domain`	Yes	Domain, e.g. example.com
`format`	No	Output verbosity.
`protocol`	No	Limit to one agent protocol (a2a, mcp or https). Omit to sweep all.
`verify_cap`	No	Fetch each cap= capability document over HTTPS and check its cap-sha256 pin. Default false.
`force_refresh`	No	Bypass the cache.

Output Schema

Name	Required	Description	Default
`score`	Yes
`passed`	Yes
`partial`	No
`category`	Yes
`findings`	Yes
`checkStatus`	No
`verdictWithheld`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed5 schema fields changedNov 12, 2026

changedInput schema / properties / domain / description

Previous value: -"Domain to check for published agent-discovery records (e.g., example.com)."New value: +"Domain, e.g. example.com"

changedInput schema / properties / force_refresh / description

Previous value: -"Bypass cache and run a fresh check. Useful after DNS changes."New value: +"Bypass the cache."

changedInput schema / properties / format / description

Previous value: -"Output verbosity. Auto-detected if omitted."New value: +"Output verbosity."

changedInput schema / properties / protocol / description

Previous value: -"Scope discovery to a single agent protocol (_index._{protocol}._agents and _{protocol}._agents). Omit to sweep every protocol."New value: +"Limit to one agent protocol (a2a, mcp or https). Omit to sweep all."

changedInput schema / properties / verify_cap / description

Previous value: -"Fetch each declared capability document (cap=) over HTTPS via safeFetch and verify it against the cap-sha256 integrity pin. Default false (declaration/existence check only)."New value: +"Fetch each cap= capability document over HTTPS and check its cap-sha256 pin. Default false."

Changed1 schema field changedNov 3, 2026

changedInput schema / properties / protocol / description

Previous value: -"Scope discovery to a single agent protocol index (_index._{protocol}._agents). Omit to sweep the zone."New value: +"Scope discovery to a single agent protocol (_index._{protocol}._agents and _{protocol}._agents). Omit to sweep every protocol."

Changed1 schema field changedOct 25, 2026
- addedInput schema / additionalProperties
```
Added value: +false
```
Changed1 schema field changedOct 5, 2026
- addedOutput schema / properties / verdictWithheld
```
Added value: +{
+  "type": "boolean"
+}
```
Changed2 schema fields changedAug 18, 2026
- addedOutput schema / properties / checkStatus
```
Added value: +{
+  "type": "string"
+}
```
- addedOutput schema / properties / partial
```
Added value: +{
+  "type": "boolean"
+}
```
AddedJul 2, 2026

TDQS

A4.1/5.0

Behavior4/5

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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive, so the description's restatement of 'Read-only' adds little. It does add real context beyond the annotations: unsigned discovery zones mean spoofable endpoints, and the records use Private-Use SVCB code points pending IANA assignment, which is a meaningful caveat about result stability and interoperability.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three dense sentences that front-load the core function before the read-only and code-point caveats. Tight and jargon-heavy but every clause conveys information; no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return-value explanation is not required, and the annotations cover the safety profile. The description covers what is checked and the key operational caveat, leaving only minor points (caching behavior behind force_refresh, compact vs full output) to the schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

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 goes slightly further by explaining what capability-document integrity means (cap/cap-sha256), which gives context for the verify_cap flag beyond the schema's own wording.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific verb and resource: it finds SVCB agent records under _agents, evaluates DANE/TLSA binding trust, and checks cap/cap-sha256 documents. The scope is narrow enough ('IETF BANDAID agent-discovery') to distinguish it from generic siblings like check_svcb_https, check_dane, and check_dnssec without naming them.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied by the resource scope (auditing agent-discovery records) but the description never says when to choose this over check_svcb_https, check_dane, or check_dnssec. There are no prerequisites or exclusions stated, although it notes it only applies to BANDAID-style zones.

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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