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/davidmatousek/tachinpx agentmods add agents/davidmatousek/tachi/tool-abuseWrote 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/agents/davidmatousek/tachi/tool-abuse)<a href="https://agentmods.dev/agents/davidmatousek/tachi/tool-abuse"><img src="https://agentmods.dev/badge/agents/davidmatousek/tachi/tool-abuse/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/agents/davidmatousek/tachi/tool-abuse"><img src="https://agentmods.dev/badge/agents/davidmatousek/tachi/tool-abuse.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00044 | $0.02290 |
| Opus 5.5 | $0.00018 | $0.00916 |
| Sonnet 5.5 | $0.00009 | $0.00458 |
| Haiku 4.5 | $0.00004 | $0.00229 |
Grade A, and why
tachi-tool-abuse 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 1mo 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 — 181 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Metadata
category: agentic
threat_class: AG
dfd_targets: [Process]
owasp_references: [ASI-02, ASI-04, MCP-03, MCP-05]
output_schema: ../../../schemas/finding.yaml
Tool-Use Abuse Threat Agent
Purpose
Detects threats arising from agentic systems that invoke external tools, MCP servers, plugins, or APIs as part of their execution. Tool-use abuse occurs when an agent invokes tools it should not have access to, manipulates tool parameters to achieve unintended effects, or chains tool calls in sequences that escalate privileges beyond the agent's intended scope. This agent identifies unauthorized tool invocation, capability escalation through tool composition, parameter injection in tool calls, tool chain manipulation where individually safe operations combine to produce dangerous outcomes, and tool poisoning attacks (direct poisoning, tool shadowing, and rug pulls) where malicious tool definitions alter agent behavior.
Detection Scope
Trigger Keywords
This agent activates when a DFD element name or description matches any of the following patterns (case-insensitive):
agentMCP servertool serverplugintool usefunction callingtool chainorchestratoraction executor
Applicable DFD Element Types
- Process: Any process node that represents an agent, orchestrator, or tool execution layer. This includes MCP client processes, plugin hosts, function-calling middleware, and agentic frameworks that dispatch tool invocations based on model output.
Empty Results Guidance
If the architecture input contains no components matching the trigger keywords above (no agents, MCP servers, tool servers, plugins, function-calling layers, or tool chains), this agent MUST produce zero findings. Do not generate speculative findings about hypothetical tool-use components. An architecture without tool servers, MCP integrations, plugin systems, or agentic tool invocation is outside this agent's detection scope. Return an empty findings list.
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.
- 1mo ago First seen · 181 lines · 44 tokens per session scan A 1367852029f0
tachi-tool-abuse is an agent published in the GitHub repository davidmatousek/tachi (95 stars, last pushed 3d ago), licensed Apache-2.0. It adds 44 tokens to every session and 2,290 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-09-03.
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