Prompt captures
The system prompt Claude Code sends.
The system array and the tool descriptions, taken from the request body a sandboxed client sent to a mock API. Byte for byte what went over the wire.
The injected-prompt ledger covers everything else the client puts on the wire: the compaction instruction, a subagent request’s own system prompt, and the conditional <system-reminder> blocks.
27 model strings · 21 system documents · 28 tool descriptions
Captured from: Claude Code, interactive mode, seeded with flags-account / Agent SDK, print mode / Agent SDK, print mode, seeded with flags-anon / Agent SDK, print mode, seeded with flags-account / Claude Code, interactive mode / Claude Code, interactive mode, seeded with flags-anon. The arms are kept separate because their prompts genuinely differ.
v2.1.250
No change to the system prompt since v2.1.248.
v2.1.248
3 of 28 tool descriptions changed. The appended system-reminder blocks moved: 2 lines added, 1 line removed.
now 27 model strings · 21 system documents · 28 tool descriptions
v2.1.247
No change to the system prompt since v2.1.246.
v2.1.246
The appended system-reminder blocks moved: 1 line added.
v2.1.242
1 of 27 tool descriptions changed.
v2.1.235
1 added and 1 removed, of 225 lines, about 3 words, in the prompt 17 of 27 arms receive.
- Calling Agent with subagent_type: "fork" creates a fork — it inherits your full conversation context, runs in the back...
v2.1.234
No change to the system prompt since v2.1.233.
v2.1.233
1 added and 1 removed, of 225 lines, about 19 words, in the prompt 17 of 27 arms receive. 3 other prompts also changed. 1 of 27 tool descriptions changed. The appended system-reminder blocks moved: 1 line added, 1 line removed.
v2.1.232
1 added and 2 removed, of 224 lines, about 173 words, in the prompt 17 of 27 arms receive. 1 of 27 tool descriptions changed.
- Calling Agent with subagent_type: "fork" creates a fork — it inherits your full conversation context, runs in the back...
v2.1.231
No change to the system prompt since v2.1.229.
v2.1.229
1 of 27 tool descriptions changed.
v2.1.228
No change to the system prompt since v2.1.227.
v2.1.227
1 added and 1 removed, of 225 lines, about 3 words, in the prompt 17 of 27 arms receive. 3 other prompts also changed. 1 of 27 tool descriptions changed.
description: {{one-line summary, used to decide relevance in future conversations, so be specific}}
v2.1.224
1 of 27 tool descriptions changed.
v2.1.223
The appended system-reminder blocks moved: 1 line removed.
v2.1.222
No change to the system prompt since v2.1.221.
v2.1.221
1 added and 1 removed, of 225 lines, about 2 words, in the prompt 17 of 27 arms receive. 3 other prompts also changed.
- Fast mode for Claude Code uses Claude Opus with faster output (it does not downgrade to a smaller model). It can be to...
v2.1.220
No change to the system prompt since v2.1.219.
v2.1.219
2 added and 2 removed, of 225 lines, about 10 words, in the prompt 17 of 27 arms receive. 2 other prompts also changed. 1 new prompt appeared. 2 of 27 tool descriptions changed.
- The most recent Claude models are the Claude 5 family and Haiku 4.5. Model IDs — Fable 5: 'claude-fable-5', Opus 5: 'c...
now 27 model strings · 21 system documents · 27 tool descriptions
v2.1.218
1 of 27 tool descriptions changed. The appended system-reminder blocks moved: 1 line removed.
v2.1.217
1 of 27 tool descriptions changed.
v2.1.216
1 of 27 tool descriptions changed.
v2.1.215
The appended system-reminder blocks moved: 2 lines removed.
v2.1.211
1 of 27 tool descriptions changed.
v2.1.208
2 added and 0 removed, of 225 lines, about 62 words, in the prompt 17 of 27 arms receive. 2 other prompts also changed.
When you use a pronoun for someone — the user or anyone else you mention — and their pronouns haven't been stated, use t...
v2.1.207
1 prompt changed. 1 of 27 tool descriptions changed.
v2.1.203
2 of 27 tool descriptions changed. The appended system-reminder blocks moved: 3 lines added, 1 line removed.
v2.1.202
1 of 27 tool descriptions changed.
v2.1.201
No change to the system prompt since v2.1.200.
v2.1.200
1 added and 1 removed, of 223 lines, about 425 words, in the prompt 17 of 27 arms receive. The appended system-reminder blocks moved: 1 line added, 1 line removed.
When you encounter an obstacle, do not use destructive actions as a shortcut to simply make it go away. For instance, tr...
v2.1.199
1 of 27 tool descriptions changed.
v2.1.198
1 added and 1 removed, of 223 lines, about 79 words, in the prompt 17 of 27 arms receive. 5 of 27 tool descriptions changed. The appended system-reminder blocks moved: 2 lines added, 1 line removed.
When you encounter an obstacle, do not use destructive actions as a shortcut to simply make it go away. For instance, tr...
v2.1.197
3 added and 3 removed, of 223 lines, about 124 words, in the prompt 17 of 27 arms receive. 2 other prompts also changed. 1 of 27 tool descriptions changed.
- You are powered by the model named Sonnet 5. The exact model ID is claude-sonnet-5.
v2.1.196
1 added and 1 removed, of 223 lines, about 2 words, in the prompt 17 of 27 arms receive. 2 other prompts also changed. 1 of 27 tool descriptions changed.
- Fast mode for Claude Code uses Claude Opus with faster output (it does not downgrade to a smaller model). It can be to...
now 27 model strings · 22 system documents · 27 tool descriptions
v2.1.187
The appended system-reminder blocks moved: 3 lines added, 3 lines removed.
v2.1.186
1 of 26 tool descriptions changed. The appended system-reminder blocks moved: 1 line added, 1 line removed.
now 27 model strings · 22 system documents · 26 tool descriptions
v2.1.178
3 of 25 tool descriptions changed. The appended system-reminder blocks moved: 9 lines added.
v2.1.177
No change to the system prompt since v2.1.176.
v2.1.176
1 of 25 tool descriptions changed.
v2.1.172
1 prompt changed. 1 of 25 tool descriptions changed.
v2.1.170
1 added and 1 removed, of 223 lines, about 15 words, in the prompt 17 of 27 arms receive. 1 other prompt also changed. 1 new prompt appeared. 1 of 25 tool descriptions changed. The appended system-reminder blocks moved: 1 line added, 1 line removed.
- The most recent Claude models are Fable 5 and the Claude 4.X family. Model IDs — Fable 5: 'claude-fable-5', Opus 4.8: ...
v2.1.169
2 added and 0 removed, of 223 lines, about 45 words, in the prompt 17 of 27 arms receive. 1 other prompt also changed.
v2.1.166
1 of 25 tool descriptions changed.
v2.1.165
No change to the system prompt since v2.1.163.
v2.1.163
1 of 25 tool descriptions changed. The appended system-reminder blocks moved: 3 lines added, 3 lines removed.
v2.1.162
1 of 25 tool descriptions changed.
v2.1.161
1 of 25 tool descriptions changed.
v2.1.160
1 of 25 tool descriptions changed.
v2.1.157
1 of 25 tool descriptions changed.
v2.1.156
No change to the system prompt since v2.1.154.
v2.1.154
4 added and 4 removed, of 221 lines, about 119 words, in the prompt 17 of 27 arms receive. 1 new prompt appeared. 9 of 25 tool descriptions changed.
- You are powered by the model named Sonnet 4.6. The exact model ID is claude-sonnet-4-6.
now 27 model strings · 22 system documents · 25 tool descriptions
v2.1.153
No change to the system prompt since v2.1.152.
v2.1.152
1 of 24 tool descriptions changed.
v2.1.142
1 of 24 tool descriptions changed.
v2.1.141
No change to the system prompt since v2.1.140.
v2.1.140
1 added and 1 removed, of 221 lines, about 7 words, in the prompt all 27 arms receive. 1 of 24 tool descriptions changed.
- Fast mode for Claude Code uses Claude Opus with faster output (it does not downgrade to a smaller model). It can be to...
v2.1.139
8 added and 5 removed, of 221 lines, about 158 words, in the prompt all 27 arms receive. 1 of 24 tool descriptions changed.
name: {{short-kebab-case-slug}}
v2.1.133
1 of 24 tool descriptions changed.
v2.1.129
2 added and 2 removed, of 218 lines, about 46 words, in the prompt all 27 arms receive. 1 of 24 tool descriptions changed.
- You are powered by the model named Opus 4.7 (1M context). The exact model ID is claude-opus-4-7[1m].
v2.1.128
1 of 24 tool descriptions changed.
v2.1.120
2 added and 1 removed, of 218 lines, about 3 words, in the prompt all 27 arms receive. 2 of 24 tool descriptions changed.
- Is a git repository: false
v2.1.119
First capture in the ledger, so there is nothing to compare it against yet.
now 27 model strings · 22 system documents · 24 tool descriptions
v2.1.118
1 new prompt appeared. 1 prompt disappeared. 22 of 23 tool descriptions changed.
now 27 model strings · 22 system documents · 23 tool descriptions
v2.1.10
1 of 17 tool descriptions changed.
v2.1.9
2 added and 2 removed, of 144 lines, about 131 words, in the prompt all 27 arms receive.
# No time estimates
v2.1.8
1 of 17 tool descriptions changed.
v2.1.7
1 of 17 tool descriptions changed.
v2.1.6
1 of 17 tool descriptions changed.
v2.1.5
No change to the system prompt since v2.1.4.
v2.1.4
1 prompt disappeared. 1 of 17 tool descriptions changed.
now 27 model strings · 1 system documents · 17 tool descriptions
v2.1.3
1 new prompt appeared. 1 of 17 tool descriptions changed.
now 27 model strings · 2 system documents · 17 tool descriptions
v2.1.0
First capture in the ledger, so there is nothing to compare it against yet.
v2.1.245to v2.1.243 2 releases, no change to the system prompt. 24-25 Aug 2026
v2.1.241to v2.1.236 6 releases, no change to the system prompt. 19-22 Aug 2026
v2.1.241
No change to the system prompt since v2.1.240.
v2.1.240
No change to the system prompt since v2.1.239.
v2.1.239
No change to the system prompt since v2.1.238.
v2.1.238
No change to the system prompt since v2.1.237.
v2.1.237
No change to the system prompt since v2.1.236.
v2.1.236
No change to the system prompt since v2.1.235.
v2.1.226to v2.1.225 2 releases, no change to the system prompt. 7-8 Aug 2026
v2.1.214to v2.1.212 3 releases, no change to the system prompt. 16-18 Jul 2026
v2.1.210to v2.1.209 2 releases, no change to the system prompt. 14 Jul 2026
v2.1.206to v2.1.204 3 releases, no change to the system prompt. 8-9 Jul 2026
v2.1.195to v2.1.190 4 releases, no change to the system prompt. 24-26 Jun 2026
v2.1.185to v2.1.179 5 releases, no change to the system prompt. 16-20 Jun 2026
v2.1.175to v2.1.173 3 releases, no change to the system prompt. 11-12 Jun 2026
v2.1.168to v2.1.167 2 releases, no change to the system prompt. 6 Jun 2026
v2.1.159to v2.1.158 2 releases, no change to the system prompt.
v2.1.150to v2.1.143 8 releases, no change to the system prompt.
v2.1.150
No change to the system prompt since v2.1.149.
v2.1.149
No change to the system prompt since v2.1.148.
v2.1.148
No change to the system prompt since v2.1.147.
v2.1.147
No change to the system prompt since v2.1.146.
v2.1.146
No change to the system prompt since v2.1.145.
v2.1.145
No change to the system prompt since v2.1.144.
v2.1.144
No change to the system prompt since v2.1.143.
v2.1.143
No change to the system prompt since v2.1.142.