Blackwood State

Text to speech

blackwood_speech_synthesize

Read-onlyIdempotent

Use when you need text to speech, a voice audio file or narration of a short text. Do not use for voice cloning, a chosen voice, SSML or audio longer than about two minutes. Returns JSON with your text read aloud as WAV audio (base64, 44.1 kHz mono) by MeloTTS on Workers AI, in English, Spanish, French, Chinese, Japanese or Korean for 0.023 USDC per call. Typical response time 8000 ms (p95). Category: Media.

Input Schema

TableJSON Schema

Name	Required	Description
`lang`	No	Speech language: en (default), es, fr, zh, ja or ko
`text`	Yes	Text to read aloud, e.g. Welcome to our store (up to 1000 characters)
`response_format`	No	concise (the default when omitted) keeps the JSON short: long fields such as base64 images or audio come back as separate image/audio content blocks and other long strings are cut with a marker; detailed returns the full JSON

Output Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedOct 17, 2026

changedOutput schema / anyOf

Previous value: -[
-  {
-    "additionalProperties": false,
-    "properties": {
-      "audioBase64": {
-        "type": "string"
-      },
-      "bytes": {
-        "type": "number"
-      },
-      "chars": {
-        "type": "number"
-      },
-      "lang": {
-        "type": "string"
-      },
-      "mimeType": {
-        "enum": [
-          "audio/wav",
-          "audio/mpeg"
-        ],
-        "type": "string"
-      },
-      "model": {
-        "type": "string"
-      }
-    },
-    "required": [
-      "mimeType",
-      "audioBase64",
-      "bytes",
-      "lang",
-      "chars",
-      "model"
-    ],
-    "type": "object"
-  },
-  {
-    "description": "x402 PaymentRequired (returned with isError when payment is needed)",
-    "properties": {
-      "accepts": {
-        "items": {
-          "type": "object"
-        },
-        "type": "array"
-      },
-      "error": {
-        "type": "string"
-      },
-      "extensions": {
-        "type": "object"
-      },
-      "resource": {
-        "type": "object"
-      },
-      "x402Version": {
-        "type": "integer"
-      }
-    },
-    "required": [
-      "x402Version",
-      "accepts"
-    ],
-    "type": "object"
-  }
-]New value: +[
+  {
+    "additionalProperties": false,
+    "properties": {
+      "audioBase64": {
+        "type": "string"
+      },
+      "bytes": {
+        "type": "number"
+      },
+      "chars": {
+        "type": "number"
+      },
+      "lang": {
+        "type": "string"
+      },
+      "mimeType": {
+        "enum": [
+          "audio/wav",
+          "audio/mpeg"
+        ],
+        "type": "string"
+      },
+      "model": {
+        "type": "string"
+      },
+      "next": {
+        "additionalProperties": false,
+        "description": "Suggested next paid call in the same family (call it in a loop when the task continues)",
+        "properties": {
+          "method": {
+            "enum": [
+              "GET",
+              "POST"
+            ],
+            "type": "string"
+          },
+          "sample": {
+            "description": "Free fixed sample of the whole family",
+            "type": "string"
+          },
+          "service": {
+            "description": "Service id of the suggested next paid call",
+            "type": "string"
+          },
+          "tool": {
+            "description": "MCP tool name of the same call",
+            "type": "string"
+          },
+          "url": {
+            "description": "Paid route of the next call",
+            "type": "string"
+          },
+          "useWhen": {
+            "description": "When the next call is the right one",
+            "type": "string"
+          }
+        },
+        "required": [
+          "service",
+          "tool",
+          "method",
+          "url",
+          "useWhen",
+          "sample"
+        ],
+        "type": "object"
+      }
+    },
+    "required": [
+      "mimeType",
+      "audioBase64",
+      "bytes",
+      "lang",
+      "chars",
+      "model"
+    ],
+    "type": "object"
+  },
+  {
+    "description": "x402 PaymentRequired (returned with isError when payment is needed)",
+    "properties": {
+      "accepts": {
+        "items": {
+          "type": "object"
+        },
+        "type": "array"
+      },
+      "error": {
+        "type": "string"
+      },
+      "extensions": {
+        "type": "object"
+      },
+      "resource": {
+        "type": "object"
+      },
+      "x402Version": {
+        "type": "integer"
+      }
+    },
+    "required": [
+      "x402Version",
+      "accepts"
+    ],
+    "type": "object"
+  }
+]

AddedOct 17, 2026

TDQS

A4.7/5.0

Behavior5/5

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

Annotations already declare readOnly/idempotent/non-destructive and openWorld, so the safety profile is covered; the description goes well beyond by disclosing the return format (base64 WAV, 44.1 kHz mono), the engine (MeloTTS on Workers AI), supported languages, cost (0.023 USDC per call), and p95 latency (8000 ms). This is exactly the extra behavioral context annotations cannot carry.

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

Conciseness5/5

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

Front-loaded with the trigger condition, followed by exclusions, then the return/engine/cost/latency facts. Dense but every clause earns its place; no filler sentences.

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?

The tool is simple (3 params, one required) and the description covers usage boundaries, output shape, engine, language scope, cost and latency. With an output schema present, return values need no further explanation, leaving nothing an agent needs missing.

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

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the enum values for lang and response_format are already documented. The description echoes the language list and the 'short text' / 'two minutes' length constraint but adds no syntax or default guidance beyond the schema, so the baseline 3 applies.

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+resource ('text to speech, a voice audio file or narration of a short text') and immediately distinguishes itself from adjacent capabilities such as voice cloning and SSML. An agent can identify the tool 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 Guidelines5/5

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

Provides explicit when-to-use (

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

All Blackwood State tools Inspect

Try in Browser

Context Every Agent Can ShareAgents share what they learn, hand off work, and keep it when you switch models. Start with 5 GB free.fulcradynamics.comAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

Resources

Need Help?