Review and correct SKILL.md for accuracy and completeness

Found six real flags with zero mention anywhere in the doc:
--source-type, --source-name, --source-id, --source-prompt, --meta-json,
--dry-run. Added a new "Source & Provenance Fields" section for the
source-* flags and covered the rest inline/in Rules.

Fixed:
- html_full's cheat-sheet entry overstated the requirement as needing
  doctype/html/head/body; the actual check only requires <html>.
- The "Images Inside Content" section had grown to cover four unrelated
  topics (images, CSV/JSON, xlsx, code-as-markdown) under a header
  describing only the first one. Split into properly-titled sections:
  Images Inside Content, CSV/JSON/Spreadsheets, Other Code.
- An unclosed parenthesis in the xlsx limitations paragraph, rewritten as
  a bulleted list for clarity while fixing it.
- Nothing anywhere mentioned that this script only creates artifacts -
  update/delete need the raw API, sharing is feed-UI-only with no API
  path at all. Added an explicit scope note.
- --source-name's actual default (the resolved source, which can come
  from DAYBOOK_SOURCE, not just --source) was previously undocumented
  entirely, so "same as --source" would have been imprecise once added.

Added: available --theme values (report/tasks/base) and which kinds
ignore it, and a note that markdown/html_fragment tables now render
styled automatically (from this session's earlier CSS pass).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

skills/daybook-posting/SKILL.md

@@ -41,15 +41,25 @@ DAYBOOK_SOURCE=agent
 
 | Kind | Use for | Content shape |
 |---|---|---|
-| `markdown` | Reports, briefs, notes | Markdown text. Fenced code blocks get syntax highlighting. |
+| `markdown` | Reports, briefs, notes | Markdown text. Fenced code blocks get syntax highlighting; tables (pipe syntax) render styled automatically. |
-| `html_fragment` | Themed HTML reports/cards/tables | Body-only HTML. No `html/head/body`. |
+| `html_fragment` | Themed HTML reports/cards/tables | Body-only HTML. No `html/head/body`. Tables render styled automatically, same as markdown. |
-| `html_full` | Complete custom pages/frameworks | Full HTML document with doctype/html/head/body. See "CDN Snippets" below. |
+| `html_full` | Complete custom pages/frameworks | Full HTML document containing `<html>` (`<!doctype>` recommended, not required). See "CDN Snippets" below. |
 | `deck` | Simple slide-like artifact | Top-level `<section>...</section>` blocks. |
 | `json` | Structured data, metrics, run summaries | Valid JSON text. Renders as a collapsible tree. |
-| `csv` | Tabular data | CSV text, first row as header. Renders as a sortable/searchable table. |
+| `csv` | Tabular data | CSV text, first row as header. Renders as a sortable/searchable table. `.xlsx` files convert to this automatically — see below. |
 
 For images, PDFs, SVGs, and other files, use `--file`; the helper infers multipart and content type.
 
+`--theme` (for `markdown`/`html_fragment` only) accepts `report` (default —
+serif, warm background), `tasks`, or `base` (minimal, no color styling).
+`deck`/`html_full`/`json`/`csv` ignore `--theme` — each has its own fixed
+presentation.
+
+This script only **creates** artifacts — none of the following are
+possible through it. Updating an existing artifact's title/tags/metadata,
+or deleting one, requires the raw API (see `docs/api.md`); enabling its
+public share link is feed-UI-only, with no API equivalent at all yet.
+
 ## CDN Snippets For `html_full`
 
 `html_full` is Daybook's escape hatch for custom pages — nothing is
@@ -111,6 +121,8 @@ python skills/daybook-posting/scripts/daybook_post.py report.md
 The image is linked to the artifact that references it and is deleted along with it.
 Unreferenced uploads are cleaned up after 24 hours.
 
+## CSV, JSON, And Spreadsheets
+
 For CSV and JSON, use `--kind csv`/`--kind json` with `--content-file` — or
 just post the file positionally; auto-mode detects `.csv`/`.json` and picks
 the right kind automatically:
@@ -127,15 +139,44 @@ python skills/daybook-posting/scripts/daybook_post.py --kind json --title "Run S
 python skills/daybook-posting/scripts/daybook_post.py balance_sheet.xlsx
 ```
 
-The server converts it to a `csv` artifact automatically (active sheet
+The server converts it to a `csv` artifact automatically. Known
-only; see `docs/api.md` for the full list of conversion limitations —
+limitations (see `docs/api.md` for the full list):
-notably, formulas need to have been calculated by real spreadsheet software
-that saved the file, and rich formatting like bold/colors/merged cells
-isn't preserved).
 
-For other code that should render today, use `--file path --as-markdown` to
+- Only the workbook's **active sheet** converts; other sheets are dropped.
-post it as a Markdown fenced code block. Without `--as-markdown`, it uploads
+- Formula cells need to have been calculated and saved by real spreadsheet
-as a downloadable binary file.
+  software (Excel, LibreOffice, etc.) — a workbook a script wrote but never
+  opened in a real spreadsheet app will show those cells blank.
+- Rich formatting (bold, colors, merged cells) isn't preserved — it's a
+  plain sortable/searchable table either way.
+- Legacy `.xls` isn't supported, only `.xlsx`.
+
+## Other Code
+
+For code that isn't CSV/JSON but should render today rather than download
+as a binary, use `--file path --as-markdown` to wrap it in a Markdown
+fenced code block (still gets syntax highlighting):
+
+```bash
+python skills/daybook-posting/scripts/daybook_post.py --file script.py --as-markdown --title "Generated Script"
+```
+
+Without `--as-markdown`, it uploads as a downloadable binary file instead.
+
+## Source & Provenance Fields
+
+All optional, all default to something reasonable if omitted:
+
+| Flag | Default | Notes |
+|---|---|---|
+| `--source-type` | `agent` | One of `agent`, `person`, `system`. |
+| `--source-name` | Same as the effective source (`--source`, or `DAYBOOK_SOURCE` if `--source` wasn't given) | Human-readable name, e.g. "Hermes Agent". |
+| `--source-id` | Empty string | A stable external ID, if the poster has one. |
+| `--source-prompt` | Empty string | The prompt/instruction that produced this artifact — useful for later tracing why something was posted. |
+
+Use `--meta key=value` (repeatable) or `--meta-json '{"key": "value"}'`
+(merged together if both are given) for structured, machine-readable
+context like `run_id` or `model` — these end up in the artifact's
+`metadata` field, distinct from tags.
 
 ## Rules
 
@@ -144,3 +185,4 @@ as a downloadable binary file.
 - Use `--tags a,b,c` for filtering.
 - Use `--meta run_id=... --meta model=...` for machine-readable context.
 - Never inline multiline content into the shell command; use a file or stdin.
+- Add `--dry-run` to see exactly what would be sent (method, headers, payload) without actually posting — useful when unsure a payload is well-formed.