1 min lesson
Tab, Chat and Agent mode
Match each case in "Tab, Chat and Agent mode" to the signal and response that fit it.
Step 1 of 2
Three surfaces, three latency budgets, three completely different failure shapes - and users describe all of them as "the AI is dumb."
Your value in a Tab/Chat/Agent ticket is converting that vague complaint into a surface and a reproducible scenario. A latency gripe about Tab and a runaway Agent edit have nothing in common except the user's frustration. Name the surface first.
Ultra-low-latency next-edit prediction as you type, often multi-line and cross-file.
Happy path: sub-second, anticipates the edit you're already making.
Complaints cluster on latency and quality: slow suggestions, irrelevant completions or Tab going quiet.
Conversational Q&A grounded in your code, no edits applied unless you act.
Happy path: accurate answers about the open codebase.
Failures trace to context: it can't see the file the user means or indexing is stale.
Multi-step, multi-file edits with tool use: reads code, runs commands, proposes a diff.
Happy path: a scoped task lands with a reviewable diff.
Failures: stale context, wrong model, rate limits, tool/permission errors, off-target edits.
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Advanced table
The failure-mode map
The failure-mode mapwhat to suspect, by symptom
- Symptom
- "Completions are slow / laggy"
- Likely surface
- Tab
- First thing to check
- Network round-trip, region, large file, conflicting extension hijacking the keybinding
- Symptom
- "Tab stopped suggesting"
- Likely surface
- Tab
- First thing to check
- File type/language, Tab disabled in settings, quota/plan limits
- Symptom
- "It gives wrong or generic answers"
- Likely surface
- Chat / Agent
- First thing to check
- Indexing state and whether the right context was attached
- Symptom
- "The agent edited the wrong files"
- Likely surface
- Agent
- First thing to check
- Scope of the prompt, context provided, model selected
- Symptom
- "Model error / request failed"
- Likely surface
- Chat / Agent
- First thing to check
- Rate limits, model availability, network/proxy, auth token
- Symptom
- "It won't run my command / read my file"
- Likely surface
- Agent
- First thing to check
- Tool permissions and what the user approved
| Symptom | Likely surface | First thing to check |
|---|---|---|
| "Completions are slow / laggy" | Tab | Network round-trip, region, large file, conflicting extension hijacking the keybinding |
| "Tab stopped suggesting" | Tab | File type/language, Tab disabled in settings, quota/plan limits |
| "It gives wrong or generic answers" | Chat / Agent | Indexing state and whether the right context was attached |
| "The agent edited the wrong files" | Agent | Scope of the prompt, context provided, model selected |
| "Model error / request failed" | Chat / Agent | Rate limits, model availability, network/proxy, auth token |
| "It won't run my command / read my file" | Agent | Tool permissions and what the user approved |
Most tickets resolve to one row. Confirm the symptom, then check the named cause.
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Optional practice