ChainHelix for Machines

mev_pressure

Read-only

MEV pressure per pool per minute on one chain: for every pool with detected MEV in the window, rows by type (sandwich, backrun, frontrun, arbitrage, jit, nft_mev), distinct victims and attackers, profit where measured, median gas multiple, first and last event. Plus the per-minute series of the chain, or of one pool when pool is given, and the chain metrics of its newest minute. window in minutes, default 60, max 1440; limit pools, default 50, max 200. Types overlap: a backrun transaction also emits an arbitrage row, so rows is a row count. Chains covered: bnb, ethereum, polygon, avalanche. Price: 1 cent per call.

Input Schema

Name	Required	Description
`pool`	No	Pool: a 0x address of 40 hex characters or a 0x pool id of 64 hex characters; absent = every pool. Example: 0x36696169c63e42cd08ce11f5deebbcebae652050
`chain`	No	One of bnb, ethereum, polygon, avalanche; default bnb. Example: ethereum
`limit`	No	Number of pools, whole number 1 to 200, default 50. Example: 20
`window`	No	Window in whole minutes, 1 to 1440, default 60. Example: 15

Output Schema

Name	Required	Description
`pool`	No
`chain`	No
`error`	No
`pools`	No
`rules`	No
`source`	No
`totals`	No
`minutes`	No
`dataGaps`	No	Present only when the window of the answer overlaps a recorded data gap. Figures inside each listed period are incomplete. periods are the recorded gaps (end null while still open); atCall is measured against the window of this call and is left out of meta.contentHash.
`generated`	No
`chainMinute`	No
`latestEventAt`	No
`windowMinutes`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed4 schema fields changedOct 25, 2026

addedInput schema / properties / chain / description

Added value: +"One of bnb, ethereum, polygon, avalanche; default bnb. Example: ethereum"

addedInput schema / properties / limit / description

Added value: +"Number of pools, whole number 1 to 200, default 50. Example: 20"

addedInput schema / properties / pool / description

Added value: +"Pool: a 0x address of 40 hex characters or a 0x pool id of 64 hex characters; absent = every pool. Example: 0x36696169c63e42cd08ce11f5deebbcebae652050"

addedInput schema / properties / window / description

Added value: +"Window in whole minutes, 1 to 1440, default 60. Example: 15"

Changed1 schema field changedOct 16, 2026

changedInput schema / x-lexicon / bundleSha256

Previous value: -"670f7504e3de5031beccee25a2d24e4515f68b893295f6d5b0d3a0665498b2c9"New value: +"25cc80db6d8e9eac73d47a50f7ad6333a21f1972d008a8fed0159de8bfb4b519"

Changed2 schema fields changedOct 16, 2026

changedInput schema / x-lexicon / bundleSha256

Previous value: -"e5b4290024a229f2bdf97f8fc6a0079c3fe13b77267f41fdcffeb8b26aa1c41e"New value: +"670f7504e3de5031beccee25a2d24e4515f68b893295f6d5b0d3a0665498b2c9"

changedInput schema / x-lexicon / version

Previous value: -"0.1.0"New value: +"0.2.0"

Changed5 schema fields changedOct 15, 2026

addedInput schema / additionalProperties
```
Added value: +false
```

addedOutput schema / properties / dataGaps

Added value: +{
+  "additionalProperties": false,
+  "description": "Present only when the window of the answer overlaps a recorded data gap. Figures inside each listed period are incomplete. periods are the recorded gaps (end null while still open); atCall is measured against the window of this call and is left out of meta.contentHash.",
+  "properties": {
+    "gaps": {
+      "items": {
+        "additionalProperties": false,
+        "properties": {
+          "atCall": {
+            "additionalProperties": false,
+            "properties": {
+              "note": {
+                "type": "string"
+              },
+              "periodsInWindow": {
+                "items": {
+                  "additionalProperties": false,
+                  "properties": {
+                    "end": {
+                      "type": "number"
+                    },
+                    "ongoing": {
+                      "type": "boolean"
+                    },
+                    "start": {
+                      "type": "number"
+                    }
+                  },
+                  "required": [
+                    "start",
+                    "end"
+                  ],
+                  "type": "object"
+                },
+                "type": "array"
+              },
+              "shareOfWindowPct": {
+                "type": "number"
+              },
+              "windowEnd": {
+                "type": "number"
+              },
+              "windowStart": {
+                "type": "number"
+              }
+            },
+            "required": [
+              "windowStart",
+              "windowEnd",
+              "periodsInWindow",
+              "shareOfWindowPct",
+              "note"
+            ],
+            "type": "object"
+          },
+          "chain": {
+            "type": "string"
+          },
+          "data": {
+            "type": "string"
+          },
+          "periods": {
+            "items": {
+              "additionalProperties": false,
+              "properties": {
+                "end": {
+                  "type": [
+                    "number",
+                    "null"
+                  ]
+                },
+                "ongoing": {
+                  "type": "boolean"
+                },
+                "start": {
+                  "type": "number"
+                }
+              },
+              "required": [
+                "start",
+                "end"
+              ],
+              "type": "object"
+            },
+            "type": "array"
+          },
+          "records": {
+            "items": {
+              "additionalProperties": false,
+              "properties": {
+                "lost": {
+                  "type": [
+                    "number",
+                    "null"
+                  ]
+                },
+                "lostUnit": {
+                  "type": [
+                    "string",
+                    "null"
+                  ]
+                },
+                "record": {
+                  "type": "string"
+                },
+                "source": {
+                  "type": "string"
+                }
+              },
+              "required": [
+                "source",
+                "record"
+              ],
+              "type": "object"
+            },
+            "type": "array"
+          },
+          "section": {
+            "type": "string"
+          },
+          "window": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "section",
+          "chain",
+          "data",
+          "window",
+          "periods",
+          "records",
+          "atCall"
+        ],
+        "type": "object"
+      },
+      "type": "array"
+    },
+    "statement": {
+      "type": "string"
+    }
+  },
+  "required": [
+    "statement",
+    "gaps"
+  ],
+  "type": "object"
+}

removedOutput schema / properties / meta

Removed value: -{
-  "additionalProperties": false,
-  "properties": {
-    "contentHash": {
-      "type": "string"
-    },
-    "generated": {
-      "type": "number"
-    },
-    "priceUsd": {
-      "type": "number"
-    },
-    "validUntil": {
-      "type": "number"
-    }
-  },
-  "type": "object"
-}

addedOutput schema / properties / pools / items / properties / zeroGasRows
```
Added value: +{
+  "type": "number"
+}
```

removedOutput schema / properties / receipt

Removed value: -{
-  "additionalProperties": false,
-  "properties": {
-    "bytes": {
-      "type": "number"
-    },
-    "covers": {
-      "type": "string"
-    },
-    "issuedAt": {
-      "type": "number"
-    },
-    "lookup": {
-      "type": "string"
-    },
-    "network": {
-      "type": [
-        "string",
-        "null"
-      ]
-    },
-    "nonce": {
-      "type": "string"
-    },
-    "seq": {
-      "type": "number"
-    },
-    "settleTx": {
-      "type": [
-        "string",
-        "null"
-      ]
-    },
-    "sha256": {
-      "type": "string"
-    },
-    "tool": {
-      "type": [
-        "string",
-        "null"
-      ]
-    }
-  },
-  "type": "object"
-}

Changed1 schema field changedSep 21, 2026

changedInput schema / x-lexicon / bundleSha256

Previous value: -"a1c2e10fd3177d6b4d59ca78693e8fb36880165cf0f735f680dd86a510411178"New value: +"e5b4290024a229f2bdf97f8fc6a0079c3fe13b77267f41fdcffeb8b26aa1c41e"

Changed1 schema field changedSep 19, 2026

changedInput schema / x-lexicon / bundleSha256

Previous value: -"1eeb782ee15fe69fc80776948e0556fa6b795e210e6305935b2c97b73d955cda"New value: +"a1c2e10fd3177d6b4d59ca78693e8fb36880165cf0f735f680dd86a510411178"

Changed1 schema field changedSep 19, 2026

changedInput schema / x-lexicon / bundleSha256

Previous value: -"c014292cad7497ce9fd68c33345ac32cb42b672c8e77d6c749c26e162cc207e4"New value: +"1eeb782ee15fe69fc80776948e0556fa6b795e210e6305935b2c97b73d955cda"

Changed3 schema fields changedSep 19, 2026

addedInput schema / x-aliases

Added value: +{
+  "limit": [
+    "Limit",
+    "limits",
+    "$limit",
+    "_limit",
+    "Limits"
+  ],
+  "pool": [
+    "pools",
+    "_pool"
+  ]
+}

addedInput schema / x-lexicon

Added value: +{
+  "bundleSha256": "c014292cad7497ce9fd68c33345ac32cb42b672c8e77d6c749c26e162cc207e4",
+  "name": "ChainHelix Agentic Lexicon",
+  "resolve": "lexicon_resolve",
+  "spec": "lexicon_spec",
+  "version": "0.1.0"
+}

addedInput schema / x-vocab

Added value: +{
+  "chain": "onchain.chain",
+  "limit": "data.limit",
+  "pool": "defi.pool",
+  "window": "market.window"
+}

AddedSep 16, 2026

TDQS

A3.8/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Consistent with readOnlyHint=true, and the description adds real behavior beyond annotations: a stated cost of '1 cent per call', the caveat that types overlap so 'rows is a row count' (a genuine misinterpretation trap), and the fact that the newest minute's chain metrics are included. It omits any note on data freshness/latency for the series.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

One dense but front-loaded paragraph: purpose first, then output shape, then parameter limits, then caveats and cost. Some sentences duplicate structured data (window/limit defaults and caps, the chain enum list), which is wasted space against a schema that already states them.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 4-param read tool with an output schema and readOnly annotation, this covers nearly everything an agent needs: aggregation definitions, the overlap caveat, chain coverage, caps, and per-call price. Remaining gaps are freshness/recency of the per-minute series and no cross-reference to the MEV siblings an agent might otherwise pick.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3, but the description adds meaning the schema does not: 'of one pool when pool is given' clarifies that pool changes the shape of the returned series rather than just filtering it, and it restates window/limit semantics in prose. The type-overlap note also affects how limit/window results should be read.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific resource and scope: 'MEV pressure per pool per minute on one chain', then enumerates the exact aggregates returned (victims, attackers, profit, median gas multiple, first/last event) and the per-minute series. An agent knows precisely what this returns, but nothing in the text differentiates it from siblings such as mev_intel, mev_pool_check, mev_bots, or victim_flow.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is only implied by the parameter semantics: omit 'pool' for the chain-wide series, supply it for a single-pool series. Defaults and caps (window 60/1440, limit 50/200) and the covered chain set are given, but there is no explicit 'use this instead of X when Y' guidance against the several other MEV tools in the sibling list.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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