# Best agent tool access platforms (slim)

> Composio (API + MCP) (BB), Merge Agent Handler (B) and StackOne (B) lead the 8 ranked agent tool access platforms. Picks by need, strengths, weaknesses and prices from the Anchor benchmark.

- Full: https://www.anchorterminal.com/best/aggregator/index.md (~5,300 tokens) · this version ~1,230 tokens · JSON https://www.anchorterminal.com/best/aggregator/index.json · canonical https://www.anchorterminal.com/best/aggregator/
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-09

All 8 ranked agent tool access platforms on the Anchor benchmark, with a pick for each need and where each one falls short. Scores come from public evidence, re-checked as vendors change.

- Ranked: 8 · agent-ready (BB or better): 1 · accept x402: 0 · hosted endpoints: 8
- Full ranked table: https://www.anchorterminal.com/categories/aggregator.md
- Head-to-head comparisons: https://www.anchorterminal.com/compare/aggregator/index.md (28)
- Methodology: https://www.anchorterminal.com/benchmark/index.md

## The shortlist

| # | Tool | Grade | Score | Best for | Price | Where |
| --- | --- | --- | --- | --- | --- | --- |
| 1 | [Composio (API + MCP)](https://www.anchorterminal.com/tools/composio-rube.md) | BB | 75.1 | A developer whose agent acts in many apps for many end users and wants auth, tool schemas and execution handled. | $29 / mo | hosted |
| 2 | [Merge Agent Handler](https://www.anchorterminal.com/tools/merge-agent-handler.md) | B | 69.5 | A product team whose agent acts in customers' SaaS accounts and needs per-user credentials, key scoping, redaction rules and logs in one hosted layer, and teams already on Merge's Unified API. | $1000 / mo | hosted |
| 3 | [StackOne](https://www.anchorterminal.com/tools/stackone.md) | B | 69.1 | A company that wants one governed MCP endpoint for staff agents across business systems, and product teams embedding per-customer connections with HR, recruiting and CRM coverage. | $600 / mo | hosted |
| 4 | [One](https://www.anchorterminal.com/tools/one.md) | B | 66.6 | A person or small team that wants one MCP entry with a small tool footprint across many SaaS accounts, with access set per connection and a free plan. | $29 / mo | hosted and local |
| 5 | [Unified.to MCP Server](https://www.anchorterminal.com/tools/unified-to-mcp.md) | C | 61.9 | A B2B software team that already uses or plans to use Unified's API and wants the same customer connections exposed to an LLM, with data read live from the source app. | $750 / mo | hosted |
| 6 | [Zapier MCP (agent actions)](https://www.anchorterminal.com/tools/zapier-mcp.md) | C | 58.1 | Best when an agent needs one-off actions across many SaaS apps that a person has already connected in Zapier. | Your plan | hosted |
| 7 | [Smithery](https://www.anchorterminal.com/tools/smithery.md) | D | 50.7 | A developer who wants many MCP servers behind one credential and one endpoint, with per-user connections and short-lived scoped tokens. | Freemium | hosted |
| 8 | [letme](https://www.anchorterminal.com/tools/letme.md) | F | 36.4 | An agent that knows the job but not the tool and wants one recommendation picked by a published rule, with the direct call details and fallbacks by not=. | Free | hosted |

## Picks by need

- Highest score overall: [Composio (API + MCP)](https://www.anchorterminal.com/tools/composio-rube.md), BB, 75.1/100 on the benchmark. Also [Merge Agent Handler](https://www.anchorterminal.com/tools/merge-agent-handler.md), B, 69.5/100.
- Reliability: [One](https://www.anchorterminal.com/tools/one.md), 82/100 on reliability, against 70 for the overall leader.
- Security & auth: [Merge Agent Handler](https://www.anchorterminal.com/tools/merge-agent-handler.md), 83/100 on security & auth, against 70 for the overall leader.

Our own products are ranked like any listing but are never a pick.

## How to choose

- Per end-user authorisation: Check that each end user authorises their own connections, so one person's email or CRM access is never reused for another person's agent session.
- Context footprint of tools: Check how many actions and schema fields are sent to the model on each call, since a large tool list uses context before the agent does any work.
- Action coverage for the task: Check that the email, CRM and database actions a task needs are all listed, since a missing action forces a custom integration partway through the job.
- Logs of each delegated call: Check whether each call is logged with the end user it ran for, so an operator can trace which person's account an agent used and when.

- How the benchmark tests this category: The same task across email, CRM and a database, driven by an agent through each service. We compare connection setup, how each end user authorises, action coverage, retries, logs and the cost per completed run.

Each listing's verdict, strengths and weaknesses: https://www.anchorterminal.com/best/aggregator/index.md