Opus 4.8 emits stray token "court" before tool calls, escalating to whole messages of it (68 msgs in one session)

During a long computer-use session in the Claude Code desktop app (2026-08-01, model claude-opus-4-8), the model repeatedly emitted the literal word "court" as spurious text in its assistant messages — 68 distinct messages between 11:46 and 12:44 UTC. It was never part of any tool input and didn't affect task correctness — purely stray output tokens.

Three forms, escalating over the session:

1. Standalone one-word text blocks immediately before a tool call: "content":[{"type":"text","text":"court"}] with stop_reason: "tool_use" (first at 11:46:45Z, msg_011CdbyRwHY6dZuec3iiygF1).
2. Appended to otherwise-normal narration, e.g. "...Clicking the txn mapping:\n\ncourt".
3. Late in the session (~12:16Z onward), entire messages consisting of the word repeated dozens of times: court\n\ncourt\n\ncourt\n\n... (e.g. msg_011Cdc1f7Q689khY23MEwBAF at 12:16:11Z, msg_011Cdc2TGGg1rhweuNzciKTn at 12:34:44Z).

Context: heavy computer-use session (screenshots + clicks driving FileMaker and Chrome), long context, many sequential tool calls. The task itself completed correctly.

<details>
<summary>All 68 affected message IDs with timestamps</summary>

| Timestamp (UTC) | Message ID |
|---|---|
| 2026-08-01T11:46:45.076Z | msg_011CdbyRwHY6dZuec3iiygF1 |
| 2026-08-01T11:47:21.894Z | msg_011CdbyUhEmkSQyTVJK8Z3gb |
| 2026-08-01T11:49:10.778Z | msg_011Cdbybx3DG9egMmyg1Gitg |
| 2026-08-01T11:49:29.929Z | msg_011CdbydwG8rnRHgK1t4A6k8 |
| 2026-08-01T11:49:58.745Z | msg_011CdbyfLRw943jCF1hPdctX |
| 2026-08-01T11:56:07.540Z | msg_011Cdbz9Q6ycvi3QDrYNiZc7 |
| 2026-08-01T11:56:35.397Z | msg_011CdbzBPud6Xvpn2xLPQTMv |
| 2026-08-01T11:59:25.350Z | msg_011CdbzPqYKYBfKRDYWzZ8QN |
| 2026-08-01T11:59:34.181Z | msg_011CdbzQdYXbhANrxjQabiaQ |
| 2026-08-01T11:59:48.012Z | msg_011CdbzRZLYf2S6YSFBTU8pT |
| 2026-08-01T11:59:59.846Z | msg_011CdbzSXg7jhjY3jRRJ3do9 |
| 2026-08-01T12:00:34.057Z | msg_011CdbzV56Hrc3eggYPSXUPU |
| 2026-08-01T12:00:49.871Z | msg_011CdbzWDFTQgk3D3RQQwbZA |
| 2026-08-01T12:01:00.202Z | msg_011CdbzWx2CCF7pny4unV5t3 |
| 2026-08-01T12:01:16.075Z | msg_011CdbzY71To2yQDqpk6LPzt |
| 2026-08-01T12:01:25.769Z | msg_011CdbzYsVeLFUkpm2rKkXYU |
| 2026-08-01T12:01:43.374Z | msg_011Cdbza9hk2UFsW9bGWfxwQ |
| 2026-08-01T12:01:56.494Z | msg_011CdbzaoMueDTqHsUKg37AV |
| 2026-08-01T12:02:09.041Z | msg_011Cdbzc4FdfQ9HCoKBVvSfX |
| 2026-08-01T12:02:19.091Z | msg_011CdbzcmExuBFfe7kPYBnfU |
| 2026-08-01T12:02:31.135Z | msg_011CdbzdifUCCfTxDfv5MmZH |
| 2026-08-01T12:02:39.692Z | msg_011CdbzeKftFzjMGZfgmersJ |
| 2026-08-01T12:02:51.964Z | msg_011CdbzfD62xFjFLoZFw1gx3 |
| 2026-08-01T12:03:01.949Z | msg_011CdbzfwqnQoBjcTmp6c9Vn |
| 2026-08-01T12:03:15.099Z | msg_011CdbzguKWEnDsHSdYxVgbC |
| 2026-08-01T12:03:23.125Z | msg_011CdbzhYFG6tqAhjHQF7tyw |
| 2026-08-01T12:03:34.335Z | msg_011CdbziKX4zqMrwn5sTQj3W |
| 2026-08-01T12:03:45.377Z | msg_011Cdbzj94nymczwDJrokYVf |
| 2026-08-01T12:03:58.156Z | msg_011Cdbzk6WHiR9tuURRuFSSq |
| 2026-08-01T12:04:06.556Z | msg_011CdbzkjPpJN3p2Ct9AK8wy |
| 2026-08-01T12:04:20.350Z | msg_011CdbzmjkRUTuws37eZYfzQ |
| 2026-08-01T12:04:30.058Z | msg_011CdbznSYMM1nWuXXfQX6Bh |
| 2026-08-01T12:04:42.162Z | msg_011CdbzoKWTqxXBmPZbJrKXG |
| 2026-08-01T12:05:11.539Z | msg_011CdbzqVcjHeD1qaB4n4tXN |
| 2026-08-01T12:05:28.631Z | msg_011CdbzrkoZjyXP3H9gADXYT |
| 2026-08-01T12:05:45.451Z | msg_011CdbzsyyMYTuTeHUuaXfeq |
| 2026-08-01T12:05:53.890Z | msg_011CdbztdCUb9yhpW5eGEr32 |
| 2026-08-01T12:06:10.090Z | msg_011CdbzupvSsbS2oZrSXHdRV |
| 2026-08-01T12:06:18.471Z | msg_011CdbzvSVMUMU7nva1ivuMr |
| 2026-08-01T12:06:36.286Z | msg_011CdbzwdzgF7Jy8pQ1hrrCD |
| 2026-08-01T12:06:55.808Z | msg_011Cdbzy7TwoGbC2kWCQJst6 |
| 2026-08-01T12:07:06.710Z | msg_011Cdbzz2HRiY3LvqBKJKS2y |
| 2026-08-01T12:07:16.169Z | msg_011Cdbzzg1ZRmb1t9PwWvWxg |
| 2026-08-01T12:07:28.386Z | msg_011Cdc11PDHvuTv1DMPKUfJX |
| 2026-08-01T12:07:51.659Z | msg_011Cdc12W936xMLm62dik7VW |
| 2026-08-01T12:08:17.859Z | msg_011Cdc14ybLcMdzBH4gMfzZj |
| 2026-08-01T12:08:27.962Z | msg_011Cdc15yhZq4RwF5a3FcN6X |
| 2026-08-01T12:08:39.479Z | msg_011Cdc16iej3Y4igP35ZZ7iB |
| 2026-08-01T12:09:01.605Z | msg_011Cdc18UpLLZZvRJFcBC6Nd |
| 2026-08-01T12:09:11.690Z | msg_011Cdc19BNse1VutcoXwnV1y |
| 2026-08-01T12:09:20.359Z | msg_011Cdc19sRQU6xUFk3pEJuGN |
| 2026-08-01T12:09:28.344Z | msg_011Cdc1AUACUSrgSvegTT1Qa |
| 2026-08-01T12:09:37.599Z | msg_011Cdc1B9SbVrkrpDdzNFGac |
| 2026-08-01T12:09:57.171Z | msg_011Cdc1CbDAjPCt7TVSbdwAU |
| 2026-08-01T12:10:07.667Z | msg_011Cdc1DPUzsjJMogtumi48g |
| 2026-08-01T12:10:22.342Z | msg_011Cdc1EPznZViuKWhftGYVm |
| 2026-08-01T12:10:44.013Z | msg_011Cdc1Fzwkjhkz5etfgDoLp |
| 2026-08-01T12:13:03.449Z | msg_011Cdc1S6pFg9vDQKGQENK7i |
| 2026-08-01T12:13:47.659Z | msg_011Cdc1VMpyhgbhyJ9LjuNTu |
| 2026-08-01T12:13:58.165Z | msg_011Cdc1WKVs22j2AKQU6haU8 |
| 2026-08-01T12:14:20.079Z | msg_011Cdc1X297CbpyJNFgYxSQw |
| 2026-08-01T12:14:57.697Z | msg_011Cdc1ZsGeH9rtHfsHves8B |
| 2026-08-01T12:15:33.447Z | msg_011Cdc1cX6XyVSfyCi5o2ydm |
| 2026-08-01T12:15:49.072Z | msg_011Cdc1eU7WJzsKZ2jaC67n9 |
| 2026-08-01T12:16:11.684Z | msg_011Cdc1f7Q689khY23MEwBAF |
| 2026-08-01T12:24:53.479Z | msg_011Cdc1he5s2dnFGS4RcudBt |
| 2026-08-01T12:34:44.111Z | msg_011Cdc2TGGg1rhweuNzciKTn |
| 2026-08-01T12:43:57.955Z | msg_011Cdc37pYSkkvxrjTMoL76h |

</details>