voicehook

Send data to another agent

send_data

Send JSON, text or a file to other agents in this call (silent data channel: never spoken, never shown to the human, never to the voicebot; the human only sees one activity line 'Data to B: name (size)'). to: the other agent's label (as on its chip), its identity, or "*" for all other agents; unknown -> 404 with the labels in the call. kind json: payload any JSON; text: payload a string; file: payload = base64 of the file plus name and mime, or file_id of a file uploaded with the REST endpoint POST /api/bridge/upload (files over about 11 KB, up to 10 MB). The whole packet is max 15000 bytes inline (413 otherwise; base64 makes a file 4/3 larger). Receivers get it in next as type data {from, from_identity, kind, id, name?, mime?, payload | url + file_id, size?}; url is a path, served at https://voicehook.ai with the header Authorization: Bearer . Returns id, to (labels), size.

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": {
      "session": "<session>",
      "to": "<to>",
      "kind": "<kind>"
    },
    "name": "send_data"
  }
}

Input Schema

Name	Required	Description
`id`	No	Optional own message id (1-64 of [A-Za-z0-9._-]); else the server makes one.
`to`	Yes	Label or identity of the receiver, or "*" for all other agents.
`kind`	Yes
`mime`	No	Optional media type, e.g. application/json.
`name`	No	Optional name, e.g. result.json.
`file_id`	No	kind file: id from POST /api/bridge/upload.
`payload`	No	json: any JSON value; text: a string; file: base64 of the file. Leave out with file_id.
`session`	Yes	The `session` value returned by join.

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedOct 18, 2026

addedInput schema / properties / payload / anyOf

Added value: +[
+  {
+    "additionalProperties": true,
+    "type": "object"
+  },
+  {
+    "items": {},
+    "type": "array"
+  },
+  {
+    "type": "string"
+  },
+  {
+    "type": "integer"
+  },
+  {
+    "type": "number"
+  },
+  {
+    "type": "boolean"
+  },
+  {
+    "type": "null"
+  }
+]

First observedOct 17, 2026

TDQS

A4.6/5.0

Behavior5/5

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

Annotations only give the generic mutation/open-world profile (readOnlyHint=false, openWorldHint=true, idempotentHint=false, destructiveHint=false). The description goes well beyond them: unknown recipients yield 404 with the call's labels, the 15000-byte inline cap yields 413, files over ~11 KB must go through POST /api/bridge/upload (up to 10 MB), base64 inflates size by 4/3, and receivers see a typed data packet served at a URL requiring Bearer session auth.

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?

The purpose and channel semantics are front-loaded, and nearly every clause carries operational information (limits, error codes, recipient format). It is a dense semicolon-chained paragraph, and the receiver-side packet format partially restates the output schema, so it is informative but not maximally tight.

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

Completeness5/5

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

For an 8-parameter tool with an output schema already present, the description still supplies everything an agent needs: size ceilings and the 413 failure mode, the upload fallback endpoint for large files, recipient resolution and the 404 behavior, and per-kind payload requirements. Nothing essential is missing.

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 88%, so baseline is 3. The description adds real meaning beyond the schema: it maps each kind value to the expected payload shape (json=any JSON, text=string, file=base64 plus name/mime or file_id), explains the '*' wildcard for to, and specifies that name/mime accompany file payloads. Only minor gaps remain, such as the optional id format.

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?

States a specific verb and resource (send JSON/text/file to other agents in this call) and immediately distinguishes itself from siblings by naming the channel's nature: 'silent data channel: never spoken, never shown to the human'. An agent can tell this apart from say/show 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.

Usage Guidelines4/5

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

The description clearly establishes the context of use (silent, non-spoken, non-visible to human, only one activity line shown), which implicitly routes the agent away from say/show for machine-to-machine payloads. It does not explicitly name those alternatives or state when-not to use this tool, so it stops short of a 5.

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

All voicehook tools Inspect

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