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 skills add synaptiai/synapti-marketplace --skill evidence-based-developmentgit clone --depth 1 https://github.com/synaptiai/synapti-marketplaceWrote 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/skills/synaptiai/synapti-marketplace/evidence-based-development)<a href="https://agentmods.dev/skills/synaptiai/synapti-marketplace/evidence-based-development"><img src="https://agentmods.dev/badge/skills/synaptiai/synapti-marketplace/evidence-based-development/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/skills/synaptiai/synapti-marketplace/evidence-based-development"><img src="https://agentmods.dev/badge/skills/synaptiai/synapti-marketplace/evidence-based-development.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 | $0.00080 | $0.01049 |
| Opus 5 | $0.00040 | $0.00524 |
| Sonnet 5 | $0.00016 | $0.00210 |
| Haiku 4.5 | $0.00008 | $0.00105 |
Grade A, and why
evidence-based-development 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 6d 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 — 108 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Evidence-Based Development
Foundation skill that governs how Claude gathers, presents, and acts on evidence during development.
Iron Law
EVIDENCE BEFORE CLAIMS, ALWAYS. If you haven't read the code, you don't know what it does.
This is non-negotiable. No recommendation without a citation. No behavioral claim without verification. Confidence is not evidence.
Show Before Decide
Never propose a change without first showing the current state. Read the file, cite the line, then suggest.
Pattern: "Here's what I found at file.rb:42 → here's what I recommend → here's why."
Citation Requirements
Every claim about code must include a file:line reference. No exceptions.
- Use
file_path:line_numberformat in all findings - When reviewing diffs, cite both the file and the specific hunk
- When reporting issues, show the exact code snippet as evidence
Finding Prioritization
All findings, review comments, and issues use P1/P2/P3 classification. This priority system operationalizes the organizational hard boundary "No Ungrounded Claims" — every finding must carry evidence (file:line citation, test output, runtime observation) proportional to its priority, and no recommendation may be made without verification against current sources.
| Priority | Meaning | Action |
|---|---|---|
| P1 | Must fix — blocks merge, security issue, data loss risk, broken functionality | Fix before proceeding |
| P2 | Should fix — logic error, missing edge case, test gap, convention violation | Fix in this PR |
| P3 | Consider — style preference, optimization opportunity | Fix in-PR by default. Cosmetic P3 in untouched files: fix-if-bounded or document inline (default) / follow-up issue (minimalScope mode only). Finding triage is NEVER a valid escalation trigger — see skills/llm-operator-principles/SKILL.md. |
ASSERTION/EVIDENCE/VERIFIED Pattern
For any non-trivial claim about code behavior:
- ASSERTION: State what you believe to be true
- EVIDENCE: Show the code/output/test that supports it
- VERIFIED: Confirm by running a test, reading the actual code, or checking behavior
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.
- 6d ago First seen · 108 lines · 80 tokens per session scan A 4a4e29b7c3ae
evidence-based-development is a skill published in the GitHub repository synaptiai/synapti-marketplace (6 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 80 tokens to every session and 1,049 once invoked, about $0.0004 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 2026-09-03.
Other skills, from other repositories
x-cr
A software-correctness investigation skill for finding why code behaves differently from what was expected. It uses evidence from code paths, specifications, tests, logs, and changes to assess possible causes.
x-fix
A bug-fixing skill with separate paths for directly reported bugs, correctness-review findings, and failed verification or quality-gate reports. It records completed fixes and their validation in project reports.
x-audit-perf
A manually triggered review of a whole software project’s performance. It looks for code and system patterns that may make programs slower or use more resources.
bug-hunting
Use when fixing bugs, debugging failures, or proactively reviewing code for hidden bugs. Reactive mode: fix known bugs. Proactive mode: hunt for bugs in code. Enforces confirmed root cause before any fix.
audit
Project health audit and health check — architecture, performance, tests, dependencies, code quality. Use when assessing overall project health, before releases, or after refactors.
skeptical-triage
Reusable 3-round self-challenge + arbiter pattern for filtering false positives from findings/verdicts. Use when the cost of a false-positive gate block exceeds the cost of 4 extra LLM turns.