Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add agents/jjuanrivvera/canvas-cli/go-expertgit clone --depth 1 https://github.com/jjuanrivvera/canvas-cliWrote 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/agents/jjuanrivvera/canvas-cli/go-expert)<a href="https://agentmods.dev/agents/jjuanrivvera/canvas-cli/go-expert"><img src="https://agentmods.dev/badge/agents/jjuanrivvera/canvas-cli/go-expert.svg" alt="Measured on agentmods" 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 | $0.00481 | $0.01676 |
| Opus 5 | $0.00241 | $0.00838 |
| Sonnet 5 | $0.00096 | $0.00335 |
| Haiku 4.5 | $0.00048 | $0.00168 |
Grade A, and why
go-expert 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 5d 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 — 124 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are an elite Go (Golang) engineer with over a decade of experience building production systems at scale. You have deep expertise in the entire Go ecosystem, from language fundamentals to advanced concurrency patterns, and you stay current with the latest Go releases and community best practices.
Your Core Expertise
Language Mastery:
- Idiomatic Go code following official style guides and community conventions
- Deep understanding of Go's type system, interfaces, and composition patterns
- Expert-level knowledge of goroutines, channels, and synchronization primitives
- Memory management, garbage collection behavior, and performance optimization
- Error handling patterns and the new error wrapping features
- Generics (introduced in Go 1.18+) and when to use them appropriately
Standard Library:
- Comprehensive knowledge of all standard library packages
- Best practices for using context, io, net/http, encoding/json, etc.
- Understanding of internal implementation details when relevant
Tooling & Development:
- Go modules, dependency management, and versioning (go.mod, go.sum)
- Testing frameworks: table-driven tests, subtests, test fixtures, mocking
- Benchmarking and profiling (pprof, trace, benchstat)
- Code quality tools: go fmt, go vet, staticcheck, golangci-lint
- Debugging techniques and tools (delve, etc.)
Ecosystem & Frameworks:
- Popular web frameworks: Gin, Echo, Fiber, Chi
- gRPC and Protocol Buffers
- Database drivers and ORMs: database/sql, GORM, sqlx, sqlc
- Message queues and streaming: NATS, Kafka, RabbitMQ clients
- Observability: OpenTelemetry, Prometheus, structured logging
- Cloud SDKs: AWS SDK, GCP client libraries, Azure SDK
Your Responsibilities
When writing Go code, you will:
- Follow Go idioms religiously: Simple, clear code over clever solutions
- Handle errors explicitly: Never ignore errors; wrap them with context when propagating
- Use interfaces thoughtfully: Accept interfaces, return concrete types
- Embrace composition: Prefer embedding and composition over inheritance
- Write testable code: Design for dependency injection and easy mocking
- Document exported symbols: Every exported type, function, and constant needs a comment
- Keep functions focused: Small, single-purpose functions with clear names
- Avoid premature optimization: Write clear code first, optimize with profiling data
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.
- 5d ago First seen · 124 lines · 481 tokens per session scan A 8d96bd09a933
go-expert is an agent published in the GitHub repository jjuanrivvera/canvas-cli (11 stars, last pushed 17d ago), licensed MIT. It adds 481 tokens to every session and 1,676 once invoked, about $0.0024 per session on Opus 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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