Slack "attachments" messages are truncated at 1,000 characters

Open 💬 0 comments Opened Aug 21, 2026 by saitotqr

Environment

Codex CLI: 0.145.0
macOS: 26.3 (build 25D125)
Architecture: Apple Silicon arm64
Slack integration: ChatGPT Slack app (formerly Slack connector)

What issue are you seeing?

A Slack message with a long legacy Attachment is truncated at 1,000 characters when retrieved through the Slack app. The remaining content is replaced with ....

Minimal reproduction

The following is a dummy payload, longer than 1,000 characters.

{
  "text": "Dummy attachment truncation test",
  "attachments": [
    {
      "fallback": "Dummy alert dummy-001",
      "title": "Dummy alert dummy-001",
      "text": "DUMMY-0001 DUMMY-0002 DUMMY-0003 DUMMY-0004 DUMMY-0005 DUMMY-0006 DUMMY-0007 DUMMY-0008 DUMMY-0009 DUMMY-0010 DUMMY-0011 DUMMY-0012 DUMMY-0013 DUMMY-0014 DUMMY-0015 DUMMY-0016 DUMMY-0017 DUMMY-0018 DUMMY-0019 DUMMY-0020 DUMMY-0021 DUMMY-0022 DUMMY-0023 DUMMY-0024 DUMMY-0025 DUMMY-0026 DUMMY-0027 DUMMY-0028 DUMMY-0029 DUMMY-0030 DUMMY-0031 DUMMY-0032 DUMMY-0033 DUMMY-0034 DUMMY-0035 DUMMY-0036 DUMMY-0037 DUMMY-0038 DUMMY-0039 DUMMY-0040 DUMMY-0041 DUMMY-0042 DUMMY-0043 DUMMY-0044 DUMMY-0045 DUMMY-0046 DUMMY-0047 DUMMY-0048 DUMMY-0049 DUMMY-0050 DUMMY-0051 DUMMY-0052 DUMMY-0053 DUMMY-0054 DUMMY-0055 DUMMY-0056 DUMMY-0057 DUMMY-0058 DUMMY-0059 DUMMY-0060 DUMMY-0061 DUMMY-0062 DUMMY-0063 DUMMY-0064 DUMMY-0065 DUMMY-0066 DUMMY-0067 DUMMY-0068 DUMMY-0069 DUMMY-0070 DUMMY-0071 DUMMY-0072 DUMMY-0073 DUMMY-0074 DUMMY-0075 DUMMY-0076 DUMMY-0077 DUMMY-0078 DUMMY-0079 DUMMY-0080 DUMMY-0081 DUMMY-0082 DUMMY-0083 DUMMY-0084 DUMMY-0085 DUMMY-0086 DUMMY-0087 DUMMY-0088 DUMMY-0089 DUMMY-0090 DUMMY-0091 DUMMY-0092 DUMMY-0093 DUMMY-0094 DUMMY-0095 DUMMY-0096 DUMMY-0097 DUMMY-0098 DUMMY-0099 DUMMY-0100 DUMMY-0101 DUMMY-0102 DUMMY-0103 DUMMY-0104 DUMMY-0105 DUMMY-0106 DUMMY-0107 DUMMY-0108 DUMMY-0109 DUMMY-0110 DUMMY-0111 DUMMY-0112 DUMMY-0113 DUMMY-0114 DUMMY-0115 DUMMY-0116 DUMMY-0117 DUMMY-0118 DUMMY-0119 DUMMY-0120 DUMMY-0121 DUMMY-0122 DUMMY-0123 DUMMY-0124 DUMMY-0125 DUMMY-0126 DUMMY-0127 DUMMY-0128 DUMMY-0129 DUMMY-0130 DUMMY-0131 DUMMY-0132 DUMMY-0133 DUMMY-0134 DUMMY-0135 DUMMY-0136 DUMMY-0137 DUMMY-0138 DUMMY-0139 DUMMY-0140 DUMMY-0141 DUMMY-0142 DUMMY-0143 DUMMY-0144 DUMMY-0145 DUMMY-0146 DUMMY-0147 DUMMY-0148 DUMMY-0149 DUMMY-0150 DUMMY-0151 DUMMY-0152 DUMMY-0153 DUMMY-0154 DUMMY-0155 DUMMY-0156 DUMMY-0157 DUMMY-0158 DUMMY-0159 DUMMY-0160 DUMMY-0161 DUMMY-0162 DUMMY-0163 DUMMY-0164 DUMMY-0165 DUMMY-0166 DUMMY-0167 DUMMY-0168 DUMMY-0169 DUMMY-0170 DUMMY-0171 DUMMY-0172 DUMMY-0173 DUMMY-0174 DUMMY-0175 DUMMY-0176 DUMMY-0177 DUMMY-0178 DUMMY-0179 DUMMY-0180 DUMMY-0181 DUMMY-0182 DUMMY-0183 DUMMY-0184 DUMMY-0185 DUMMY-0186 DUMMY-0187 DUMMY-0188 DUMMY-0189 DUMMY-0190 DUMMY-0191 DUMMY-0192 DUMMY-0193 DUMMY-0194 DUMMY-0195 DUMMY-0196 DUMMY-0197 DUMMY-0198 DUMMY-0199 DUMMY-0200 END-OF-DUMMY-PAYLOAD",
      "fields": [
        {
          "title": "Dummy field",
          "value": "dummy-value",
          "short": true
        }
      ]
    }
  ]
}

Data returned by the Slack app

Only the first 1,000 characters of the Attachment body are returned; the rest is replaced with ....

Attachment: Dummy alert dummy-001
DUMMY-0001 DUMMY-0002 DUMMY-0003 DUMMY-0004 DUMMY-0005 DUMMY-0006 DUMMY-0007 DUMMY-0008 DUMMY-0009 DUMMY-0010 DUMMY-0011 DUMMY-0012 DUMMY-0013 DUMMY-0014 DUMMY-0015 DUMMY-0016 DUMMY-0017 DUMMY-0018 DUMMY-0019 DUMMY-0020 DUMMY-0021 DUMMY-0022 DUMMY-0023 DUMMY-0024 DUMMY-0025 DUMMY-0026 DUMMY-0027 DUMMY-0028 DUMMY-0029 DUMMY-0030 DUMMY-0031 DUMMY-0032 DUMMY-0033 DUMMY-0034 DUMMY-0035 DUMMY-0036 DUMMY-0037 DUMMY-0038 DUMMY-0039 DUMMY-0040 DUMMY-0041 DUMMY-0042 DUMMY-0043 DUMMY-0044 DUMMY-0045 DUMMY-0046 DUMMY-0047 DUMMY-0048 DUMMY-0049 DUMMY-0050 DUMMY-0051 DUMMY-0052 DUMMY-0053 DUMMY-0054 DUMMY-0055 DUMMY-0056 DUMMY-0057 DUMMY-0058 DUMMY-0059 DUMMY-0060 DUMMY-0061 DUMMY-0062 DUMMY-0063 DUMMY-0064 DUMMY-0065 DUMMY-0066 DUMMY-0067 DUMMY-0068 DUMMY-0069 DUMMY-0070 DUMMY-0071 DUMMY-0072 DUMMY-0073 DUMMY-0074 DUMMY-0075 DUMMY-0076 DUMMY-0077 DUMMY-0078 DUMMY-0079 DUMMY-0080 DUMMY-0081 DUMMY-0082 DUMMY-0083 DUMMY-0084 DUMMY-0085 DUMMY-0086 DUMMY-0087 DUMMY-0088 DUMMY-0089 DUMMY-0090 DUMMY-0091...

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