Runs an independent, adversarial verification of an AI-coding-agent context-reduction proxy's (rtk, headroom) claimed token and cost savings, using the same TT01-TT05 engine as tokentrust verify on the command line: a real local tokenizer (tiktoken, cl100k_base) and the bundled 23-task labeled corpus, with the proxy invoked as a real subprocess rather than re-running the vendor's own benchmark script. Call this when an agent needs a trustworthy, third-party number for a proxy's actual compression ratio, cost delta, or output-safety guard -- e.g. before recommending a proxy, evaluating a version upgrade, or checking a CI regression -- not for general token counting or for proxies outside {rtk, headroom} (headroom is recognized but not yet runnable; the report notes this rather than failing). No API key or network access is required in the default (non-live) mode, which estimates cost from published pricing tables; it only needs the proxy binary and a task corpus to already be present on disk.

Side effects: read-only against repo (the proxy runs against the task corpus; the target repo itself is never modified) and it appends a versioned run record keyed by run_id to local on-disk history so a later TT05 call can diff a new run against the prior one for the same proxy/repo pair -- safe to retry, but not idempotent output-wise, since every run gets a fresh run_id. Setting BOTH live and confirmCost to true additionally makes real, provider-billed API calls against your own key (env-configured, never passed as a parameter) for up to liveMaxTasks tasks; omit either one and zero network calls are made. A failed or refused run (missing proxy binary, invalid task corpus, or the live safety gate declining the call) still returns a CallToolResult with isError=true and a JSON {ok: false, exit_code, message} body explaining why, instead of throwing.

Parameters: proxy (required) is a proxy name or array of names from {rtk, headroom} -- pass an array to run TT04's cross-tool comparison in one call. repo (optional) is a filesystem path, defaulting to this server's own working directory. tasks (optional) is a path to a tokentrust-tasks.yml corpus, defaulting to the bundled 23-task set. live/confirmCost (optional booleans, both false by default) gate real billed sampling as described above. liveMaxTasks (optional integer, default 5) caps how many tasks live mode samples. Example calls: {"proxy": "rtk"} for a standard estimated-cost run against the bundled corpus; {"proxy": ["rtk", "headroom"], "repo": "/path/to/target-repo"} for a side-by-side TT04 comparison against a specific repo; {"proxy": "rtk", "live": true, "confirmCost": true, "liveMaxTasks": 3} to verify the cost estimate against 3 real, billed samples.

Returns: the same structured JSON tokentrust verify --format json produces on success -- run_id, timestamp, repo, task_corpus_size, proxies, a records array (one entry per proxy/category with claimed_savings_pct vs measured_savings_pct), plus tt03 (never-worse guard pass/fail per proxy) and tt05 (version-drift regression pass/fail per proxy) maps. Run tokentrust verify --help on the command line for the full flag reference this schema mirrors.