xlsx: `$B$6`-style references in SKILL.md are rewritten by Claude Code's `$N` argument substitution
What happens
In Claude Code, $0–$9 in a skill body are argument placeholders: $0 is the first word of the arguments, $1 the second, and so on. skills/xlsx/SKILL.md has three Excel absolute references, and each contains one:
When the skill is invoked with a multi-word argument, those references reach Claude rewritten. On Claude Code 2.1.273, with this SKILL.md (at fa0fa64) copied unmodified into .claude/skills/xlsx/ and the request captured by a local stub:
| Invocation | Line 53 | Line 78 | Line 94 |
|---|---|---|---|
/xlsx budget.xlsx |
$B$2 |
$B$5 |
$B$6 |
/xlsx fix formulas in budget.xlsx |
$Bin |
$B$5 |
$B$6 |
/xlsx build a three statement model for fiscal year revenue |
$Bthree |
$Bfor |
$Bfiscal |
A single-word argument is safe, since it only fills $0. Claude also passes arguments when it invokes a skill itself, through the Skill tool's args, and that path substitutes the same way (anthropics/claude-code#94496).
These lines are the skill's guidance on how to write references (link to assumption cells, quote sheet names), so the corrupted versions are the worst place for it: =B5*(1+$Bfiscal) is not a valid formula.
I tested it as a project skill rather than through the document-skills plugin, because anthropics/claude-code#94762 reports that the plugin's inline skills currently don't register on recent versions. The body is the same either way once the skill loads.
Possible fixes
- Escape the digit's
$in SKILL.md, as Claude Code documents:$B\$2,$B\$5,$B\$6. On 2.1.273, with that change, the longest invocation above delivers all three as$B$2,$B$5,$B$6. I haven't checked how other Claude surfaces that load this SKILL.md treat the backslash, which is the open question for this option. - Fix it in Claude Code instead. anthropics/claude-code#94709 has a follow-up proposing that
$0–$9expand only in skills that declareargument-hintorarguments(xlsx declares neither), and never directly after a letter or digit, as in$B$6. That would fix this skill without changing it.
The other document skills (docx, pptx, pdf) have no $<digit> in their SKILL.md.
Source: anthropics/skills