Tool · Claude Code · Anthropic

Read

claude-code/readRead · primarysourcechecked 2026-09-02
How this differs from most implementations
  • Staleness check before writeinvariantholdsvs fails in 6 of 8
  • Whichever hits firstlinesvs lines or bytes in 4 of 5

Derived by comparing every recorded value against the other implementations of the same capability. Differing is not a defect unless the row is marked an invariant.

Observed · Read

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Output shape
Dedicated read toolReadsrc
Line numberingN + TABsrc
Matches the output of cat -n.
Output wrapperplainsrc
Limits
Default line cap2000src
Byte / char cap
Per-line cap2000 charssrc
Whichever hits firstlinessrc
Pagination
Offset base1-indexedsrc
Announces truncationinvariantholdssrc
Emitted on truncation.
Continuation hinton truncationsrc
Reports total lines?
Out-of-range offset?
Non-text
Binary content never enters context silentlyinvariantholdssrc
Refuses binary files.
Binary filesrefusesrc
Imagesinlinesrc
PDFspages param, max 20/reqsrc
Notebookscells + outputssrc
Giant single lineper-line capsrc
Errors
Missing patherrorsrc
Path is a directoryerrorsrc
Empty fileexplicit remindersrc
Non-vision model
Correctness
Mixed line endings?
Staleness check before writeinvariantholdssrc
Edit requires a prior read of the same file.
Line-number contamination guardinstructs model to strip prefixsrc

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