tool.describe
A Claude Code settings key, read out of the shipped bundle. No mined inventory carries it: everything below comes from what this site has written about it.
Plugin hooks are limited in what they may rewrite, and cannot take over question prompts.
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.242.
In the changelogs
11Releases whose published page names tool.describe.
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v2.1.323
Add-ons can now hook into the list of tools
Add-on code can now respond to a
tool.listevent when Claude Code lists its toolsnamed in this entry, found in this entry's text
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v2.1.317
Two internal name lists in Claude Code each gain an entry
A list holding command.describe, env.get and prompt.section now also holds tool.describe, and a list of input sources gains a mid-turn prompt entry
found in this entry's text
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v2.1.269
New
tool.checkhook event wired into the tool-approval pipelineNew tool.check hook can override a hook's earlier 'deny' decision on a tool call
found in this entry's text
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v2.1.269
New tool/config SDK operations pass through unmodified
SDK gains tool.check, config.set, and config.describe pass-through operations
found in this entry's text
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v2.1.267
Hooks engine gains session.compact, session.receive, ui.resolve event contracts
The plugin hooks system adds validated event types for session compaction, session receive, and UI resolution
found in this entry's text
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v2.1.265
ui.invalidate now supports invalidating command.describe
The ui.invalidate plugin operation can now also invalidate command.describe
found in this entry's text
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v2.1.265
Hook registry gains command.describe as a core hook event
Claude Code adds a new internal hook event called command.describe
found in this entry's text
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v2.1.259
New functionHooks event: prompt.context
A new prompt.context hook event lets plugins add named context blocks to a prompt, capped at 32 blocks and 32000 characters.
found in this entry's text
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v2.1.259
Plugin UI hooks can now invalidate on prompt.context, not just prompt.section
Plugins can now invalidate prompt.context specifically through ui.invalidate, alongside ui.render and prompt.section.
found in this entry's text
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v2.1.242
Each hook event enforces what a plugin is allowed to change
Plugin hooks are limited in what they may rewrite, and cannot take over question prompts.
found in this entry's text
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v2.1.242
Plugin modules with a
$API that can hook events and redraw the terminal UIPlugins can install code that intercepts tool calls and repaints parts of the terminal interface.
found in this entry's text
First cited
4The earliest release whose published evidence quoted tool.describe was v2.1.259, 2 Sep 2026. That is the oldest release this project wrote about it, so it is a floor on the name's age and not the release that introduced it. It is not a presence reading: which builds carried the name is the table below.
Presence across releases
0The miner has never read a build containing this name. It is here because a changelog entry of ours names it, which is evidence that it existed and not evidence of which releases carried it. The inventory starts at v2.1.138 and everything older than that was never mined.
Read out of the published npm bundle release by release, and out of Anthropic's own documentation as this site captured it. Nothing on this page is a description anybody here wrote about what the settings key does. All settings keys.