API documentation (#221)

docs/apis/api-text-completion.md

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+
+# TrustGraph Text Completion API
+
+This is a low-level interface to the LLM service.  For a higher-level
+interface with template management, consider the
+[Prompt API](api-prompt.md).
+
+## Request/response
+
+### Request
+
+Some LLM system permit specifying a separate `system` prompt.  When
+the same system prompt is used repeatedly, this can result in lower
+token costs for the system part or quicker LLM response.
+
+The request contains the following fields:
+- `system`: A string, the system part
+- `prompt`: A string, the user part
+
+### Response
+
+The request contains the following fields:
+- `response`: LLM response
+
+## REST service
+
+The REST service accepts a request object containing the question field.
+The response is a JSON object containing the `answer` field.
+
+e.g.
+
+Request:
+```
+{
+    "system": "You are a helpful agent",
+    "prompt": "What does NASA stand for?"
+}
+```
+
+Response:
+
+```
+{
+    "response": "National Aeronautics and Space Administration"
+}
+```
+
+## Websocket
+
+Requests have a `request` object containing the `system` and
+`prompt` fields.
+Responses have a `response` object containing `response` field.
+
+e.g.
+
+Request:
+
+```
+{
+    "id": "blrqotfefnmnh7de-1",
+    "service": "text-completion",
+    "request": {
+        "system": "You are a helpful agent",
+        "prompt": "What does NASA stand for?"
+    }
+}
+```
+
+Response:
+
+```
+{
+    "id": "blrqotfefnmnh7de-1",
+    "response": {
+        "response": "National Aeronautics and Space Administration"
+    },
+    "complete": true
+}
+```
+
+## Pulsar
+
+The Pulsar schema for the Text Completion API is defined in Python code here:
+
+https://github.com/trustgraph-ai/trustgraph/blob/master/trustgraph-base/trustgraph/schema/models.py
+
+Default request queue:
+`non-persistent://tg/request/text-completion`
+
+Default response queue:
+`non-persistent://tg/response/text-completion`
+
+Request schema:
+`trustgraph.schema.TextCompletionRequest`
+
+Response schema:
+`trustgraph.schema.TextCompletionResponse`
+
+## Pulsar Python client
+
+The client class is
+`trustgraph.clients.LlmClient`
+
+https://github.com/trustgraph-ai/trustgraph/blob/master/trustgraph-base/trustgraph/clients/llm_client.py
+