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 skills/sfc-gh-abannerjee/snowgram/edit_existingnpx skills add sfc-gh-abannerjee/SnowGram --skill edit_existinggit clone --depth 1 https://github.com/sfc-gh-abannerjee/SnowGramWrote 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/sfc-gh-abannerjee/snowgram/edit_existing)<a href="https://agentmods.dev/skills/sfc-gh-abannerjee/snowgram/edit_existing"><img src="https://agentmods.dev/badge/skills/sfc-gh-abannerjee/snowgram/edit_existing.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 5.1 | $0.00324 | $0.01674 |
| Opus 5 | $0.00162 | $0.00837 |
| Sonnet 5 | $0.00065 | $0.00335 |
| Haiku 4.5 | $0.00032 | $0.00167 |
Grade A, and why
edit_existing_diagram 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 — 148 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Edit existing diagram (surgical, layout-preserving)
This skill instructs the agent to edit a diagram in place by mutating the current-canvas mermaid the user is looking at, instead of regenerating from a template tool. The frontend re-renders from your output, so the edit becomes the canvas. Keeping the unchanged content byte-identical is how we avoid clobbering the user's prior manual edits and the agent's prior decisions.
Hard rules
-
Do NOT call
COMPOSE_DIAGRAM_FROM_TEMPLATEorCOMPOSE_DIAGRAM_FROM_PATTERNwhen this skill is active. Those tools produce a fresh diagram and would overwrite the user's existing one. UseSEARCH_COMPONENT_BLOCKSonly if the edit needs new components the canvas doesn't have. UseVALIDATE_MERMAID_SYNTAXafter assembling the edited mermaid. -
Start from the current-canvas mermaid in the prompt. Treat it as the source of truth. Apply the user's requested change(s), preserving every other line VERBATIM — same node IDs, same labels (typo and all), same edge directions, same subgraph structure, same class definitions, same styling. Do not "improve" or "clean up" anything the user didn't ask you to.
-
Preserve node IDs. When replacing or renaming a node's label, keep the existing id unchanged so the frontend can match it across the diff. The frontend's auto-expand and history-snapshot logic keys on indices and IDs.
-
Match the canonical response structure. Even for edits, emit:
- Section 1: Architecture Overview (1 sentence describing what the diagram shows AFTER the edit — short, do not re-describe the whole architecture)
- Section 2: Component Summary (only the components the user added, removed, or modified — not the full table)
- Section 3: Best Practices (skip if the edit doesn't introduce new practices; just write "No new best practices — see prior message.")
- Section 4: Diagram — "Here is your updated diagram:" +
mermaid(the FULL edited diagram, not a diff) + Graph Metadata JSON - Section 5: Stats — node/edge counts of the EDITED diagram
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 · 148 lines · 324 tokens per session scan A effaf6dfe494
edit_existing_diagram is a skill published in the GitHub repository sfc-gh-abannerjee/SnowGram (2 stars, last pushed 2mo ago), licensed MIT. It adds 324 tokens to every session and 1,674 once invoked, about $0.0016 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 2026-08-31.
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