Skip to main content
Glama
Sign In
Gulliver

Gulliver

by laaielichter
OverviewSchemaSourceRelated ServersDiscussionsAdmin
Python
Hybrid

gulliver_impact

Read-onlyIdempotent

Map downstream models and columns that use a table or column before changing or dropping it from SQL files or a dbt manifest; omit the target to return the model graph.

Instructions

Blast radius: which downstream models and columns use a table or table.column (column-level lineage over a folder of SQL models or a dbt manifest). Without a target it returns the model graph. Parses files only; no database needed. Use it before changing or dropping a table or column; use gulliver_drift to see what already changed in the database, gulliver_review for a whole PR.

Input Schema

NameRequiredDescriptionDefault
targetNoTable or table.column, e.g. 'raw.events' or 'raw.events.user_id'. Case-insensitive; a short name also matches a qualified one ('events' matches 'raw.events'). Omit for the whole graph.
dialectNoSQL dialect used to parse the models.duckdb
manifestNoPath to a dbt target/manifest.json (alternative to models_dir).
models_dirNoFolder with SQL models (*.sql, dbt-style refs allowed). Use an absolute path.

Output Schema

NameRequiredDescriptionDefault
statusYes
next_stepYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed2 schema fields changedv0.3.1
    • changedInput schema / properties / dialect / description
      Previous value: -"SQL dialect."New value: +"SQL dialect used to parse the models."
    • changedInput schema / properties / target / description
      Previous value: -"Table or table.column, e.g. 'raw.events.user_id'."New value: +"Table or table.column, e.g. 'raw.events' or 'raw.events.user_id'. Case-insensitive; a short name also matches a qualified one ('events' matches 'raw.events'). Omit for the whole graph."
  2. Changed3 schema fields changedv0.1.1
    • addedOutput schema / properties
      Added value: +{
+  "next_step": {
+    "type": "string"
+  },
+  "status": {
+    "enum": [
+      "ok",
+      "warn",
+      "block",
+      "needs_rehearsal",
+      "needs_approval",
+      "skipped",
+      "fail",
+      "error"
+    ],
+    "type": "string"
+  }
+}
    • addedOutput schema / required
      Added value: +[
+  "status",
+  "next_step"
+]
    • changedOutput schema / title
      Previous value: -"gulliver_impactDictOutput"New value: +"GulliverResult"
  3. First observedv0.1.0

TDQS

A4.4/5.0
Behavior4/5

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

Annotations already declare readOnly, idempotent, non-destructive, closed-world. The description adds context not in annotations: it only parses files and needs no database, which tells the agent the tool is static and safe to call without connection setup, and it discloses the default graph-returning behavior when target is omitted. Return shape detail is left to the output schema.

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

Conciseness5/5

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

Three tight sentences: capability first, default behavior second, environment constraint third, then routing guidance. No filler and nothing buried.

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?

Output schema covers return values and annotations cover the safety profile, so the description is close to complete. One small gap: with zero required parameters, it does not say what happens or fails if neither manifest nor models_dir is supplied, which an agent must infer.

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

Parameters3/5

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

Schema coverage is 100% and every parameter carries its own description, including target matching rules and manifest as an alternative to models_dir. The description reinforces the two-source idea (folder of SQL models or dbt manifest) but adds no syntax or precedence rules beyond the schema, so the baseline 3 applies.

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

Purpose5/5

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

States a specific verb and resource: downstream models and columns that use a table or table.column, computed as column-level lineage over SQL models or a dbt manifest. The no-target behavior (returns the model graph) is also stated, so the agent knows both modes without opening the schema.

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

Usage Guidelines5/5

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

Gives an explicit when: before changing or dropping a table or column. It also names two alternatives with their distinguishing conditions – gulliver_drift for changes already in the database, gulliver_review for a whole PR – so routing between siblings is unambiguous.

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

Deploy Server

Other Tools