diff --git a/docs/api.md b/docs/api.md
index e0b0036..362300e 100644
--- a/docs/api.md
+++ b/docs/api.md
@@ -28,9 +28,9 @@ Currently supported kinds:
 
 | Kind | Upload type | Rendered behavior | Raw support |
 |---|---|---|---|
-| `html_fragment` | JSON text | Wrapped with a Daybook theme | No |
-| `html_full` | JSON text | Stored as complete HTML | Yes |
-| `markdown` | JSON text | Rendered to HTML (fenced code blocks get syntax highlighting) and original `.md` is preserved | Yes |
+| `html_fragment` | JSON text | Wrapped with a Daybook theme; tables styled automatically | No |
+| `html_full` | JSON text | Stored as complete HTML, verbatim — no theme or styling injected | Yes |
+| `markdown` | JSON text | Rendered to HTML (code blocks syntax-highlighted, tables styled) and original `.md` preserved | Yes |
 | `deck` | JSON text | Wrapped as a simple HTML slide/deck page | No |
 | `image` | Multipart file | Browser image preview | No |
 | `pdf` | Multipart file | Browser PDF preview | No |
@@ -57,8 +57,13 @@ as coloured chips next to the title. The API exposes both separately, plus a com
 | `source_type` | No | `agent` | One of `agent`, `person`, `system`. |
 | `source_name` | No | `source` | Human-readable source name. |
 | `source_id` | No | Empty string | Stable external agent/person/system ID. |
+| `source_prompt` | No | Empty string | The prompt/instruction that produced the artifact. |
 | `metadata` | No | `{}` | Free-form object for model/run/tool metadata. |
 
+`source_name`, `source_id`, and `source_prompt` must be strings if provided
+— sending an object, array, or number returns `400` (they are not coerced).
+`metadata` must be an object. See "Create Text Artifact" for length limits.
+
 Example source metadata:
 
 ```json
@@ -498,10 +503,10 @@ Example response:
 
 ```json
 {
-  "artifact_kinds": ["html_fragment", "html_full", "markdown", "deck", "image", "pdf", "binary"],
+  "artifact_kinds": ["html_fragment", "html_full", "markdown", "deck", "image", "pdf", "binary", "json", "csv"],
   "filters": ["source", "label", "day", "kind", "q"],
   "views": ["rendered", "raw"],
-  "raw_supported_for": ["markdown", "html_full"],
+  "raw_supported_for": ["markdown", "html_full", "json", "csv"],
   "source_types": ["agent", "person", "system"],
   "auth": "bearer_token",
   "methods": {
@@ -512,6 +517,9 @@ Example response:
 }
 ```
 
+This is generated from the server's actual configuration, so it's the
+authoritative source if this document and a running instance ever disagree.
+
 Agents should call this endpoint if they need to adapt to the current Daybook instance, or
 simply to check the instance is reachable and their token is valid. Unlike the other read
 endpoints, it accepts a bearer token as well as a browser session:
@@ -523,8 +531,11 @@ curl -H "Authorization: Bearer <your-personal-token>" http://127.0.0.1:8001/api/
 ## Current MVP Constraints
 
 - Each user has a personal ingest API token; there is no shared token.
-- Reader/browser access requires login; feeds are private per user.
-- Content modification/revisions are deferred.
-- Office document conversion is not implemented.
+- Reader/browser access requires login; feeds are private per user (except
+  per-artifact public share links — see Sharing above).
+- Content modification/revisions are deferred (`PATCH` edits metadata only,
+  never `content`).
+- Spreadsheet conversion covers `.xlsx` → `csv` only; other Office formats
+  (`.docx`, `.pptx`, legacy `.xls`) are not converted.
 - Manual browser upload/drag-and-drop is deferred.
 - Pagination/cursors are not implemented yet.
diff --git a/docs/llm_posting_helper.md b/docs/llm_posting_helper.md
index 9794324..6cafeb6 100644
--- a/docs/llm_posting_helper.md
+++ b/docs/llm_posting_helper.md
@@ -6,6 +6,11 @@ The project also keeps `scripts/daybook_post.py` as a compatibility wrapper.
 
 The helper is intentionally zero-dependency and uses only Python's standard library. It works on Windows and Linux.
 
+It only **creates** artifacts. Updating (title/tags/metadata) and deleting
+require the raw API (`PATCH`/`DELETE /api/artifacts/{id}`, see `docs/api.md`);
+enabling a public share link is done from the feed UI and has no API or CLI
+path yet.
+
 ## Configuration
 
 Set these as real process/shell environment variables — the helper reads
@@ -64,6 +69,13 @@ python skills/daybook-posting/scripts/daybook_post.py results.csv
 python skills/daybook-posting/scripts/daybook_post.py --kind json --title "Run Summary" --content-file summary.json
 ```
 
+Post an `.xlsx` spreadsheet (converted server-side to a `csv` artifact —
+active sheet only, saved formula results only, no formatting preserved):
+
+```bash
+python skills/daybook-posting/scripts/daybook_post.py balance_sheet.xlsx
+```
+
 Render other code as a Markdown fenced block instead (no dedicated `code`
 kind yet):
 
@@ -71,6 +83,14 @@ kind yet):
 python skills/daybook-posting/scripts/daybook_post.py --file script.py --as-markdown --title "Generated Script"
 ```
 
+Embed an image inside a markdown/HTML artifact (upload first, then
+reference the printed URL in your content):
+
+```bash
+python skills/daybook-posting/scripts/daybook_post.py --upload-image chart.png
+# -> prints .../assets/<id>; put that in your markdown, then post normally
+```
+
 Dry run:
 
 ```bash
@@ -112,6 +132,21 @@ Or pass a JSON object:
 python skills/daybook-posting/scripts/daybook_post.py --kind markdown --title "Run Summary" --content-file summary.md --meta-json '{"run_id":"run-001"}'
 ```
 
+`--meta` and `--meta-json` are merged if both are given. Metadata lives in
+the artifact's `metadata` field, separate from `--tags` (which are for
+filtering).
+
+## Source & Theme Flags
+
+| Flag | Default | Notes |
+|---|---|---|
+| `--source` | `DAYBOOK_SOURCE` env, else `agent` | What produced this — an agent-profile, script, or person name. |
+| `--source-type` | `agent` | One of `agent`, `person`, `system`. |
+| `--source-name` | The effective `--source` | Human-readable name, e.g. "Hermes Agent". |
+| `--source-id` | Empty | A stable external ID, if one exists. |
+| `--source-prompt` | Empty | The prompt/instruction behind the artifact. |
+| `--theme` | Kind default | `markdown`/`html_fragment` only: `report` (default), `tasks`, or `base`. Other kinds ignore it. |
+
 ## Skill Wrapper
 
 A thin LLM-facing wrapper lives at: