document update --content and --content-file fail with Internal server error

[schpet]

linear document update fails when passing content, but works for title-only updates.

Reproduction

# Works
linear doc update abc123 --title "New Title"

# Fails — inline content
linear doc update abc123 --content "# Test heading"
# ✗ Failed to update document: Internal server error

# Fails — content from file
echo "# Test heading" > /tmp/test.md
linear doc update abc123 --content-file /tmp/test.md
# ✗ Failed to update document: Internal server error

The equivalent GraphQL mutation works fine via linear api:

linear api "$(< query.graphql)" \
  --variable 'id=aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee' \
  --variable 'content=@/tmp/test.md'

where query.graphql is:

mutation($id: String!, $content: String!) {
  documentUpdate(id: $id, input: { content: $content }) {
    success
  }
}

Side note: linear api escapes ! in query strings

Passing the query inline also breaks because ! gets backslash-escaped before being sent:

linear api 'mutation($id: String!, $content: String!) { ... }'
# Syntax Error: Unexpected character: "\".
# 1 | mutation($id: String\!, $content: String\!) { ...

Workaround is reading the query from a file via shell substitution ($(< file)).

Environment

• linear-cli 1.10.0