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 instructions/block/model-ledger/claude-mdgit clone --depth 1 https://github.com/block/model-ledgerWhat 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 | $0.01331 | $0.01331 |
| Opus 5 | $0.00665 | $0.00665 |
| Sonnet 5 | $0.00266 | $0.00266 |
| Haiku 4.5 | $0.00133 | $0.00133 |
Grade A, and why
model-ledger CLAUDE.md 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 2d 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 — 104 lines — stays where its author put it; the contents beside it link to each section on GitHub.
model-ledger
Open-source model inventory and governance framework. Apache-2.0.
Build & Test
.venv/bin/python -m pytest tests/ -v
.venv/bin/python -m pytest tests/test_file.py::test_name -v # single test
.venv/bin/python -m ruff check src/ tests/
.venv/bin/python -m ruff format src/ tests/
.venv/bin/python -m mypy src/
Architecture
v0.7.2+ (current — agent protocol + connectors + change tracking)
src/model_ledger/connectors/sql.py— sql_connector() factorysrc/model_ledger/connectors/rest.py— rest_connector() factorysrc/model_ledger/connectors/github.py— github_connector() factorysrc/model_ledger/connectors/prefect.py— prefect_connector() factory (Prefect Cloud API)src/model_ledger/backends/sqlite_ledger.py— SQLiteLedgerBackend (persistent, zero-dep)src/model_ledger/backends/snowflake.py— SnowflakeLedgerBackend (production)src/model_ledger/backends/http.py— HttpLedgerBackend (MCP → REST API pass-through)src/model_ledger/backends/json_files.py— JsonFileLedgerBackend (git-friendly)src/model_ledger/sdk/ledger.py— Ledger SDK with last_seen, change_detected/change_occurredsrc/model_ledger/tools/— 8 agent tool functions (record, query, investigate, trace, changelog, discover, tag, list_tags)src/model_ledger/mcp/server.py— MCP server (FastMCP, 8 tools + 3 resources)src/model_ledger/rest/app.py— REST API (FastAPI, create_app() factory)
v0.4.x (DataNode graph)
src/model_ledger/core/ledger_models.py— ModelRef, Snapshot, Tagsrc/model_ledger/sdk/ledger.py— Ledger SDK (register, record, tag, add, connect, trace, upstream, downstream)src/model_ledger/graph/models.py— DataNode, DataPort (with schema discriminators)src/model_ledger/graph/protocol.py— SourceConnector protocolsrc/model_ledger/backends/ledger_protocol.py— LedgerBackend protocolsrc/model_ledger/backends/ledger_memory.py— InMemory backendsrc/model_ledger/adapters/sql.py— SQL parsing (extract_tables, write_tables, model_name_filters)src/model_ledger/adapters/tables.py— Table-based pipeline discoverysrc/model_ledger/adapters/cron.py— Cron expression translation
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.
- 2d ago First seen · 104 lines · 1,331 tokens per session scan A 70a7feb84d3d
model-ledger CLAUDE.md is an instructions file published in the GitHub repository block/model-ledger (14 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 1,331 tokens to every session, about $0.0067 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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