BTrace is a Java diagnostic tool that dynamically inserts tracing into running Java applications without restarting or recompiling them. Java developers and operations teams use it to inspect methods, timings, fields, allocations, and other runtime behavior in production environments. Catalogue add-ons provide instructions for using BTrace.
Borrowing it
Nothing to install: this file belongs to btraceio/btrace. 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/btraceio/btrace/develop/AGENTS.mdgit clone --depth 1 https://github.com/btraceio/btraceWrote 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/btraceio/btrace/agents-md)<a href="https://agentmods.dev/instructions/btraceio/btrace/agents-md"><img src="https://agentmods.dev/badge/instructions/btraceio/btrace/agents-md/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/btraceio/btrace/agents-md"><img src="https://agentmods.dev/badge/instructions/btraceio/btrace/agents-md.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 | $0.00890 | $0.00890 |
| Opus 5.5 | $0.00356 | $0.00356 |
| Sonnet 5.5 | $0.00178 | $0.00178 |
| Haiku 4.5 | $0.00089 | $0.00089 |
Grade A, and why
btrace AGENTS.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 2mo 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 — 66 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Repository Guide for Coding Agents
Start here
BTrace is a Java tracing tool: the client compiles and sends a script, the agent instruments the target JVM, and the runtime emits results. The root project is a multi-module Gradle build.
btrace-agent— attachable agent, script lifecycle, and bytecode instrumentation/weavingbtrace-compiler— script verification and compilationbtrace-runtime/btrace-core— script APIs, runtime support, and protocolbtrace-client— CLI and attachment clientbtrace-dist— distribution assembly;integration-tests— end-to-end testsbtrace-extensions/*— extension API and implementations
For the developer command reference and code-navigation pointers, see CLAUDE.md. For user and contributor documentation, start at docs/README.md.
Non-negotiable rules
- Do not commit unless the changes are fully tested or the user explicitly requests a commit.
- Preserve unrelated working-tree changes.
- In Java code, import types and use simple names; do not introduce fully qualified type names in source.
- Main code targets Java 8 and uses the Java 11 toolchain. Follow Spotless/Google Java Format.
- Unit tests live in
src/test/javaand use*Test; integration tests live inintegration-tests/src/test/java. - Changes to user-visible behavior that crosses modules or process boundaries must include end-to-end functional coverage in
integration-tests; unit and component tests are required where useful but are not a substitute for exercising the real client, agent, target JVM, and protocol interaction. - Confirm that a new test or build gate fails when it should, not only that it passes. Run it against the unfixed code, or against input it must reject, and check the failure is the expected one. A check that cannot fail reports success regardless of what the code does, and reads as coverage while providing none. Where a revert is used to produce the failure, revert only the code under test: reverting too much fails for an unrelated reason and proves nothing about the behavior being asserted.
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.
- 2mo ago First seen · 66 lines · 890 tokens per session scan A 1bb964182dd8
btrace AGENTS.md is an instructions file published in the GitHub repository btraceio/btrace (5,997 stars, last pushed yesterday), licensed Apache-2.0. It adds 890 tokens to every session, about $0.0036 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.
Other instructions, from other repositories
vibetags com-example-service-OrderService.instructions.md
Instructions for PIsberg/vibetags, covering copilot instructions for orderservice, rules for method calculatetax, rules for method processpayment, rules for method validateorder and context & focus.
vibetags com-example-security-SecurityConfig.instructions.md
Instructions for PIsberg/vibetags, covering copilot instructions for securityconfig, locked status, rules for method getencryptionalgorithm, rules for method getkeyrotationhours and rules for method getmaxloginattempts.
vibetags com-example-service-TransactionalPaymentService.instructions.md
Instructions for PIsberg/vibetags, covering copilot instructions for transactionalpaymentservice and strict exception handling.
vibetags com-example-concurrent-SessionCache.instructions.md
Instructions for PIsberg/vibetags, covering copilot instructions for sessioncache and thread-safety guarantee.
vibetags com-example-config-AsyncTestConfig.instructions.md
Instructions for PIsberg/vibetags, covering copilot instructions for asynctestconfig and immutable type.
vibetags com-example-gmm-platform-FeatureGate.md
Instructions for PIsberg/vibetags, covering amazon kiro steering: featuregate and feature flag gate.