Borrowing it
Nothing to install: this file belongs to microsoft/vscode-copilot-chat. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/microsoft/vscode-copilot-chat/main/.github/instructions/model-prompts.instructions.mdgit clone --depth 1 https://github.com/microsoft/vscode-copilot-chatWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/instructions/microsoft/vscode-copilot-chat/model-prompts)<a href="https://agentmods.dev/instructions/microsoft/vscode-copilot-chat/model-prompts"><img src="https://agentmods.dev/badge/instructions/microsoft/vscode-copilot-chat/model-prompts/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/instructions/microsoft/vscode-copilot-chat/model-prompts"><img src="https://agentmods.dev/badge/instructions/microsoft/vscode-copilot-chat/model-prompts.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.01649 | $0.01649 |
| Opus 5.5 | $0.00660 | $0.00660 |
| Sonnet 5.5 | $0.00330 | $0.00330 |
| Haiku 4.5 | $0.00165 | $0.00165 |
Grade A, and why
vscode-copilot-chat model-prompts.instructions.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 194 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Guidelines for creating, registering, and testing model-specific prompts via the PromptRegistry system.
Prompt Registry
The PromptRegistry in promptRegistry.ts maps AI models to their optimal prompt structures. Each model provider has a resolver class implementing IAgentPrompt that returns prompt customizations for that provider's models.
Resolution Order
When PromptRegistry.resolveAllCustomizations() is called:
- Phase 1 —
matchesModel(): Iterates registered resolvers in order, callingmatchesModel(). Firsttruewins. - Phase 2 —
familyPrefixes: If nomatchesModelmatched, checksendpoint.family.startsWith(prefix). First match wins. - Defaults: If no resolver matches, defaults are used for all customizations.
Registration order matters — more specific resolvers (e.g., hash-based) should be registered before broader ones (e.g., prefix-based fallbacks).
Resolver Interface
The IAgentPrompt interface provides these customization methods:
| Method | Returns | Purpose |
|---|---|---|
resolveSystemPrompt(endpoint) |
SystemPrompt |
Main system prompt class |
resolveReminderInstructions?(endpoint) |
ReminderInstructionsConstructor |
Reminder instructions appended to user messages |
resolveToolReferencesHint?(endpoint) |
ToolReferencesHintConstructor |
Tool usage hints |
resolveCopilotIdentityRules?(endpoint) |
CopilotIdentityRulesConstructor |
Identity/role rules |
resolveSafetyRules?(endpoint) |
SafetyRulesConstructor |
Safety rules |
resolveUserQueryTagName?(endpoint) |
string |
Tag name wrapping user queries |
All methods are optional except resolveSystemPrompt. Unimplemented methods fall back to defaults (DefaultReminderInstructions, DefaultToolReferencesHint, etc.).
Dependency Injection in Resolvers
Resolvers are created via instantiationService.createInstance(), so they support full constructor DI. Inject IConfigurationService, IExperimentationService, etc. to read experiment flags or config values:
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 194 lines · 1,649 tokens per session scan A ddc8204d7181
vscode-copilot-chat model-prompts.instructions.md is an instructions file published in the GitHub repository microsoft/vscode-copilot-chat (9,960 stars, last pushed 5mo ago), licensed MIT. It adds 1,649 tokens to every session, about $0.0066 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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