Claim verification

Training memory describes some version of a library, often a blend of several. The user's project runs one specific version. Most hallucinated APIs fall in the gap between the two: a renamed kwarg, a flag added in a later minor release, a default that changed, a function that moved modules. This skill closes that gap cheaply. Most checks take one command.

When a claim needs checking

Check before stating anything the user will act on that names a specific:

• function, method, class, or import path
• parameter or keyword name, its type, or its default
• CLI flag, subcommand, or exit code
• config key, env var, or file location
• version number, a "since vX", or "deprecated in vX"
• behavior claim ("X retries by default", "Y is thread-safe")

Skip checking for general concepts ("Postgres supports transactions") and for code you have already opened in this session.

Where the truth is, in order of authority

1. The installed artifact itself. It's the version that will actually run.
   • CLI: <tool> --help, <tool> <sub> --help, man <tool>, <tool> --version
   • Python: python -c "import pkg, inspect; print(pkg.__version__); print(inspect.signature(pkg.fn))", or read the source at python -c "import pkg; print(pkg.__file__)"
   • Node: node_modules/<pkg>/package.json (version), its .d.ts types (signatures), and node -e "console.log(Object.keys(require('<pkg>')))"
   • Go: go doc <pkg>.<Symbol>. Rust: the source under ~/.cargo/registry/src/
   • Anything: grep the installed source for the symbol
2. The lockfile or manifest, to find which version the project pins when nothing is installed yet (package-lock.json, uv.lock, poetry.lock, Cargo.lock, go.sum)
3. Docs pinned to that version, such as versioned docs URLs, the tagged README, or the CHANGELOG entries between the version you recall and the pinned one
4. Latest docs or memory. Use these last, and say they are unpinned.

If the installed version and your memory disagree, the installed version wins. Tell the user about the mismatch, because they may be reading the same outdated docs.

Label what you say

When an answer contains specific claims, mark how you know each one. Use plain words, not a badge on every sentence:

• verified means you checked it this session against the installed version or a source you ran. Show what you ran when it's useful ("rg --help on 14.1 lists --pcre2").
• inferred means it follows from something verified but you didn't test it directly. Say what it was inferred from.
• recalled means it came from memory and wasn't checked. Say so, and give the one command that would check it if you can't run it yourself.

One sentence like "I checked these against requests 2.31 installed here; the retry default is from memory" is enough. The point is that the user can tell which claims are solid and which still need checking.

Writing code against an API

Before writing a call to an API you haven't opened this session, look up its signature first. That takes one command. Debugging a wrong kwarg costs a test run and a confused user. If the call compiles or imports cleanly in a quick check (python -c "from x import y", tsc --noEmit, go vet), that is verification. Say that you ran it.

When you can't check

No shell, the package isn't installed, or the docs are unreachable: say the claim is recalled. Name the version you believe it applies to, and give the user the exact command to confirm it. Don't hedge everything into mush. Be specific about which part is uncertain.

Example

User: "how do I set a timeout on httpx requests?"

Weak: "Pass timeout=10 to httpx.get." This is recalled and unlabeled.

Strong: runs python -c "import httpx, inspect; print(httpx.__version__); print(inspect.signature(httpx.get))", sees 0.27.0 and timeout: 'TimeoutTypes' = Timeout(timeout=5.0), then answers: "httpx.get(url, timeout=10). Verified against httpx 0.27 installed here. The default is 5 seconds, not unlimited like requests. For separate connect and read limits, use httpx.Timeout(10, connect=2). I recalled that form; it's in the same signature's Timeout class if you want to check."