Count tokens in a Message changedapi/beta/messages/count_tokens
Nearest release: v2.1.286, published an hour after this site recorded the change. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.
Recorded here
Lines+172added
Lines−180removed
From line
21
where the diff opens
First seen
14 Aug 2026
this site's first read of the page
Recorded edits16to this page, all time
The whole hunk
from line 21, old and new numbered
/
from line 21
2121
2222 - `string`
2323
24 - `"message-batches-2024-09-24" or "prompt-caching-2024-07-31" or "computer-use-2024-10-22" or 45 more`
24 - `"message-batches-2024-09-24"`
2525
26 - `"message-batches-2024-09-24"`
26 - `"prompt-caching-2024-07-31"`
2727
28 - `"prompt-caching-2024-07-31"`
28 - `"computer-use-2024-10-22"`
2929
30 - `"computer-use-2024-10-22"`
30 - `"computer-use-2025-01-24"`
3131
32 - `"computer-use-2025-01-24"`
32 - `"pdfs-2024-09-25"`
3333
34 - `"pdfs-2024-09-25"`
34 - `"token-counting-2024-11-01"`
3535
36 - `"token-counting-2024-11-01"`
36 - `"token-efficient-tools-2025-02-19"`
3737
38 - `"token-efficient-tools-2025-02-19"`
38 - `"output-128k-2025-02-19"`
3939
40 - `"output-128k-2025-02-19"`
40 - `"files-api-2025-04-14"`
4141
42 - `"files-api-2025-04-14"`
42 - `"mcp-client-2025-04-04"`
4343
44 - `"mcp-client-2025-04-04"`
44 - `"mcp-client-2025-11-20"`
4545
46 - `"mcp-client-2025-11-20"`
46 - `"dev-full-thinking-2025-05-14"`
4747
48 - `"dev-full-thinking-2025-05-14"`
48 - `"interleaved-thinking-2025-05-14"`
4949
50 - `"interleaved-thinking-2025-05-14"`
50 - `"code-execution-2025-05-22"`
5151
52 - `"code-execution-2025-05-22"`
52 - `"extended-cache-ttl-2025-04-11"`
5353
54 - `"extended-cache-ttl-2025-04-11"`
54 - `"context-1m-2025-08-07"`
5555
56 - `"context-1m-2025-08-07"`
56 - `"context-management-2025-06-27"`
5757
58 - `"context-management-2025-06-27"`
58 - `"model-context-window-exceeded-2025-08-26"`
5959
60 - `"model-context-window-exceeded-2025-08-26"`
60 - `"skills-2025-10-02"`
6161
62 - `"skills-2025-10-02"`
62 - `"fast-mode-2026-02-01"`
6363
64 - `"fast-mode-2026-02-01"`
64 - `"output-300k-2026-03-24"`
6565
66 - `"output-300k-2026-03-24"`
66 - `"user-profiles-2026-03-24"`
6767
68 - `"user-profiles-2026-03-24"`
68 - `"user-profiles-2026-08-18"`
6969
70 - `"user-profiles-2026-08-18"`
70 - `"user-profiles-2026-09-04"`
7171
72 - `"user-profiles-2026-09-04"`
72 - `"advisor-tool-2026-03-01"`
7373
74 - `"advisor-tool-2026-03-01"`
74 - `"managed-agents-2026-04-01"`
7575
76 - `"managed-agents-2026-04-01"`
76 - `"cache-diagnosis-2026-04-07"`
7777
78 - `"cache-diagnosis-2026-04-07"`
78 - `"dreaming-2026-04-21"`
7979
80 - `"dreaming-2026-04-21"`
80 - `"thinking-token-count-2026-05-13"`
8181
82 - `"thinking-token-count-2026-05-13"`
82 - `"server-side-fallback-2026-06-01"`
8383
84 - `"server-side-fallback-2026-06-01"`
84 - `"server-side-fallback-2026-07-01"`
8585
86 - `"server-side-fallback-2026-07-01"`
86 - `"fallback-credit-2026-06-01"`
8787
88 - `"fallback-credit-2026-06-01"`
88 - `"fallback-credit-2026-07-01"`
8989
90 - `"fallback-credit-2026-07-01"`
90 - `"agent-memory-2026-07-22"`
9191
92 - `"agent-memory-2026-07-22"`
92 - `"mid-conversation-tool-changes-2026-07-01"`
9393
94 - `"mid-conversation-tool-changes-2026-07-01"`
94 - `"compact-2026-01-12"`
9595
96 - `"compact-2026-01-12"`
96 - `"computer-use-2025-11-24"`
9797
98 - `"computer-use-2025-11-24"`
98 - `"mcp-tunnels-2026-06-22"`
9999
100 - `"mcp-tunnels-2026-06-22"`
100 - `"structured-outputs-2025-11-13"`
101101
102 - `"structured-outputs-2025-11-13"`
102 - `"task-budgets-2026-03-13"`
103103
104 - `"task-budgets-2026-03-13"`
104 - `"thinking-display-updates-2026-08-18"`
105105
106 - `"thinking-display-updates-2026-08-18"`
106 - `"ce-user-management-2026-07-13"`
107107
108 - `"ce-user-management-2026-07-13"`
108 - `"mid-conversation-output-config-2026-07-01"`
109109
110 - `"mid-conversation-output-config-2026-07-01"`
110 - `"thinking-binding-controls-2026-08-01"`
111111
112 - `"thinking-binding-controls-2026-08-01"`
112 - `"mid-conversation-system-clear-at-2026-08-21"`
113113
114 - `"mid-conversation-system-clear-at-2026-08-21"`
114 - `"compact-2026-09-04"`
115115
116 - `"compact-2026-09-04"`
116 - `"inline-tools-2026-09-15"`
117117
118 - `"inline-tools-2026-09-15"`
118 - `"mcp-client-2026-09-15"`
119119
120 - `"mcp-client-2026-09-15"`
121
122120- `"anthropic-user-profile-id": optional string`
123121
124122 The user profile ID to attribute this request to. Use when acting on behalf of a party other than your organization. Requires the `user-profiles` beta header.
from line 3088
30903088
30913089 See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.
30923090
3093 - `"claude-sonnet-5-5" or "claude-fable-5-1" or "claude-opus-5-5" or 16 more`
3091 - `"claude-sonnet-5-5"`
30943092
3095 The model that will complete your prompt.
3093 Efficient model for coding and agents
30963094
3097 See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.
3095 - `"claude-fable-5-1"`
30983096
3099 - `"claude-sonnet-5-5"`
3097 Frontier intelligence for ambitious tasks across coding, scientific discovery, and enterprise workflows
31003098
3101 Efficient model for coding and agents
3099 - `"claude-opus-5-5"`
31023100
3103 - `"claude-fable-5-1"`
3101 Powerful intelligence for coding, knowledge work, and long-running agents
31043102
3105 Frontier intelligence for ambitious tasks across coding, scientific discovery, and enterprise workflows
3103 - `"claude-mythos-5-1"`
31063104
3107 - `"claude-opus-5-5"`
3105 Our most capable model for cybersecurity and biology research, available through trusted access programs
31083106
3109 Powerful intelligence for coding, knowledge work, and long-running agents
3107 - `"claude-sonnet-5"`
31103108
3111 - `"claude-mythos-5-1"`
3109 Efficient model for coding and agents
31123110
3113 Our most capable model for cybersecurity and biology research, available through trusted access programs
3111 - `"claude-fable-5"`
31143112
3115 - `"claude-sonnet-5"`
3113 Next generation of intelligence for the hardest knowledge work and coding problems
31163114
3117 Efficient model for coding and agents
3115 - `"claude-mythos-5"`
31183116
3119 - `"claude-fable-5"`
3117 Most capable model for cybersecurity and biology research
31203118
3121 Next generation of intelligence for the hardest knowledge work and coding problems
3119 - `"claude-opus-5"`
31223120
3123 - `"claude-mythos-5"`
3121 Powerful intelligence for long-running agents and coding
31243122
3125 Most capable model for cybersecurity and biology research
3123 - `"claude-opus-4-8"`
31263124
3127 - `"claude-opus-5"`
3125 Powerful intelligence for long-running agents and coding
31283126
3129 Powerful intelligence for long-running agents and coding
3127 - `"claude-opus-4-7"`
31303128
3131 - `"claude-opus-4-8"`
3129 Powerful intelligence for long-running agents and coding
31323130
3133 Powerful intelligence for long-running agents and coding
3131 - `"claude-opus-4-6"`
31343132
3135 - `"claude-opus-4-7"`
3133 Powerful intelligence for long-running agents and coding
31363134
3137 Powerful intelligence for long-running agents and coding
3135 - `"claude-sonnet-4-6"`
31383136
3139 - `"claude-opus-4-6"`
3137 Best combination of speed and intelligence
31403138
3141 Powerful intelligence for long-running agents and coding
3139 - `"claude-haiku-4-5"`
31423140
3143 - `"claude-sonnet-4-6"`
3141 Fastest model with near-frontier intelligence
31443142
3145 Best combination of speed and intelligence
3143 - `"claude-haiku-4-5-20251001"`
31463144
3147 - `"claude-haiku-4-5"`
3145 Fastest model with near-frontier intelligence
31483146
3149 Fastest model with near-frontier intelligence
3147 - `"claude-opus-4-5"`
31503148
3151 - `"claude-haiku-4-5-20251001"`
3149 Powerful intelligence for long-running agents and coding
31523150
3153 Fastest model with near-frontier intelligence
3151 - `"claude-opus-4-5-20251101"`
31543152
3155 - `"claude-opus-4-5"`
3153 Powerful intelligence for long-running agents and coding
31563154
3157 Powerful intelligence for long-running agents and coding
3155 - `"claude-sonnet-4-5"`
31583156
3159 - `"claude-opus-4-5-20251101"`
3157 High-performance model for agents and coding
31603158
3161 Powerful intelligence for long-running agents and coding
3159 - `"claude-sonnet-4-5-20250929"`
31623160
3163 - `"claude-sonnet-4-5"`
3161 High-performance model for agents and coding
31643162
3165 High-performance model for agents and coding
3163 - `"claude-mythos-preview"`
31663164
3167 - `"claude-sonnet-4-5-20250929"`
3165 **Deprecated**: Will reach end-of-life on June 30, 2026. Please migrate to claude-mythos-5. Visit https://docs.anthropic.com/en/docs/resources/model-deprecations for more information.
31683166
3169 High-performance model for agents and coding
3170
3171 - `"claude-mythos-preview"`
3172
3173 **Deprecated**: Will reach end-of-life on June 30, 2026. Please migrate to claude-mythos-5. Visit https://docs.anthropic.com/en/docs/resources/model-deprecations for more information.
3174
3175 New class of intelligence, strongest in coding and cybersecurity
3167 New class of intelligence, strongest in coding and cybersecurity
31763168
31773169 - `string`
31783170
No line in this hunk matches that.