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 oborchers/fractional-cto --skill versioning-and-evolutiongit clone --depth 1 https://github.com/oborchers/fractional-ctoWrote 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/oborchers/fractional-cto/versioning-and-evolution)<a href="https://agentmods.dev/skills/oborchers/fractional-cto/versioning-and-evolution"><img src="https://agentmods.dev/badge/skills/oborchers/fractional-cto/versioning-and-evolution/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/oborchers/fractional-cto/versioning-and-evolution"><img src="https://agentmods.dev/badge/skills/oborchers/fractional-cto/versioning-and-evolution.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Data Exfiltration · line 110 Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
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 | $0.00072 | $0.02952 |
| Opus 5 | $0.00036 | $0.01476 |
| Sonnet 5 | $0.00014 | $0.00590 |
| Haiku 4.5 | $0.00007 | $0.00295 |
Grade A, and why
versioning-and-evolution 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 10d 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 — 200 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Ship V1 and Never Break It
Your API version is a promise. The moment a consumer writes code against your endpoint, you have entered a contract. Breaking that contract -- renaming a field, removing an endpoint, changing a type -- destroys trust and costs integration partners real engineering time. The best APIs treat backward compatibility as non-negotiable and version changes as a carefully managed migration, not a surprise.
Stripe has kept /v1/ stable since 2012. Over a decade, zero URL-level version bumps. They ship breaking changes behind dated version headers, and every account stays pinned to the version it was created with. This is the gold standard. Your API should aspire to the same discipline.
Versioning Strategies
Four strategies exist in production. Each has real tradeoffs.
| Strategy | Mechanism | Pros | Cons | Used By |
|---|---|---|---|---|
| URL path | /v1/resources |
Explicit, visible, cacheable, trivial to route at the gateway | URL changes break clients on major bumps, encourages big-bang migrations | Stripe, Google, Twilio, Facebook, Spotify |
| Custom header | Stripe-Version: 2024-11-20 or X-GitHub-Api-Version: 2022-11-28 |
Clean URLs, per-request granularity, enables incremental migration | Invisible in URLs, harder to debug and cache, must remember the header | Stripe (secondary), GitHub |
| Query parameter | ?api-version=2022-12-01 |
Easy to add, visible in logs | Mixes versioning with resource params, easily omitted, pollutes query string | Azure, AWS |
| Date-based header (Stripe model) | Account pinned to signup date, override with Stripe-Version header |
Granular per-request migration, no URL changes, each change documented by date | Requires version gate infrastructure internally | Stripe |
Default to URL path versioning. It is the most intuitive, most cacheable, and easiest to route. Every developer understands /v1/. Reserve header-based versioning for fine-grained control within a major version, following Stripe's hybrid model.
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.
- 10d ago First seen · 200 lines · 72 tokens per session scan A bac55a1c0aa3
versioning-and-evolution is a skill published in the GitHub repository oborchers/fractional-cto (29 stars, last pushed 1mo ago), licensed MIT. It adds 72 tokens to every session and 2,952 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 2026-08-30.
Other skills, from other repositories
mem0-oss-to-platform
Plan and then execute a migration of a project from the mem0 open-source / self-hosted SDK (the local Memory class) to the mem0 Platform / hosted / managed SDK (the MemoryClient class). Use this whenever a developer wants to move, switch, or migrate their mem0 usage off OSS/self-hosted to the hosted API — e.g.…
agui-dotnet-protobuf
Use the protobuf wire transport (instead of the default Server-Sent Events) for an AG-UI connection with the AG-UI .NET SDK — a compact binary event stream negotiated via the Accept header. USE FOR: making an AGUIChatClient prefer protobuf by wiring an AGUIEventStreamHandler with ProtobufEventStreamFormatter (then…
azure-mgmt-botservice-dotnet
Azure Resource Manager SDK for Bot Service in .NET. Management plane operations for creating and managing Azure Bot resources, channels (Teams, DirectLine, Slack), and connection settings. Triggers: "Bot Service", "BotResource", "Azure Bot", "DirectLine channel", "Teams channel", "bot management .NET", "create bot".
fastapi-router-py
Create FastAPI routers with CRUD operations, authentication dependencies, and proper response models. Use when building REST API endpoints, creating new routes, implementing CRUD operations, or adding authenticated endpoints in FastAPI applications.
migrate-segw-to-rap
Reverse-engineer a SEGW-built OData V2 service (MPC/DPC/MPCEXT/DPCEXT) into a modern RAP V4 service — tables, CDS views (interface + projection), behavior definitions, draft entities, service definition + binding. Use when asked to "migrate this SEGW service to RAP", "convert OData V2 to V4 RAP", "modernize this…
telnyx-messaging-hosted-curl
Set up hosted SMS numbers, toll-free verification, and RCS messaging. Use when migrating numbers or enabling rich messaging features. This skill provides REST API (curl) examples.