Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/mishahanin/heading-osnpx agentmods add skills/mishahanin/heading-os/corporate-letterWrote 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/mishahanin/heading-os/corporate-letter)<a href="https://agentmods.dev/skills/mishahanin/heading-os/corporate-letter"><img src="https://agentmods.dev/badge/skills/mishahanin/heading-os/corporate-letter/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/mishahanin/heading-os/corporate-letter"><img src="https://agentmods.dev/badge/skills/mishahanin/heading-os/corporate-letter.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00118 | $0.01611 |
| Opus 5 | $0.00059 | $0.00805 |
| Sonnet 5 | $0.00024 | $0.00322 |
| Haiku 4.5 | $0.00012 | $0.00161 |
Grade A, and why
corporate-letter 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 8d 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 — 158 lines — stays where its author put it; the contents beside it link to each section on GitHub.
External Letter (31C Branded)
Produce a formal external letter using the locked 31C corporate template. Renders to PDF and DOCX.
Variables
recipient: full name, title, organisationsubject: subject line (under 70 chars)objective: what this letter should accomplishcontext: relationship and situational background
Phase 0: Context Loading
Before drafting, read:
reference/corporate-style-guide.md- locked template, colors, typography, signature, checklist.claude/rules/corporate-docs.md- guardrail and pipeline.claude/rules/terminology.md- Tribe, ODUN.ONE, DPI+, Five Principles.claude/rules/voice.md- writing rulesreference/misha-voice.md(or sender's voice file if present).claude/rules/voss.md- negotiation overlaycontext/people.md- CRM relationship context if the recipient is knowncontext/pipeline.md- if this letter relates to an active pipeline entry
Phase 1: Classify and Confirm
Announce the selection before drafting:
Using
/corporate-letter(31C external letter template). PDF + DOCX will be rendered. Locked letterhead, GT Standard typography, confidentiality footer applied.
If the recipient, subject, or objective is missing, ask one targeted block of questions before drafting.
Phase 2: Draft the Letter Body
Constraints:
- First-person singular from the sender.
- Opening paragraph: peer-to-peer, not vendor. State the reason for writing in sentence one.
- Body: 1-3 short paragraphs, under 350 words total.
- Closing: one concrete next step with owner and timing.
- No round-number pricing or dates. Voss precision always.
- Use single hyphens
-never double dashes. - Never use "31 Concept GmbH" or legal-suffix variants. Always "31 Concept".
- Use "Tribe" for the company's people, never "team", "family", "crew".
The body HTML should be a sequence of <p>...</p> paragraphs. Do not include the salutation inside BODY_HTML - the salutation is a separate placeholder.
Phase 3: Present for Approval
What ships with it
3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 8d ago Changed · +1 lines 562a9dcbadb8
- 11d ago First seen · 157 lines · 118 tokens per session scan A 10c9b7f73d88
corporate-letter is a skill published in the GitHub repository mishahanin/heading-os (11 stars, last pushed 2d ago), licensed Apache-2.0. It adds 118 tokens to every session and 1,611 once invoked, about $0.0006 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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