Skip to main content
Glama
jansc4
by jansc4

Run block pipeline

run_pipeline

Run a multi-step pipeline: execute configured blocks in order, pass outputs forward, and continue even if a step fails.

Instructions

Runs a list of steps in order. Each step: a block name from REGISTRY, args, optionally save_as (remember the result under a name) and for_each (run the block once per item in a list from an earlier result, referenced as '@name.field'). For each item, either item_arg names the one argument it fills, or — if item_arg is omitted and the item is itself a dict — its keys are spread directly as keyword arguments (for blocks that take several values per call, e.g. write_file's path+content). The result of a for_each step is a list of dicts pairing each item's identifying fields with the block's output — otherwise there'd be no way to tell which result belongs to which item. A step that raises an exception doesn't stop the rest — ok=False + error land in that step's result.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
stepsYes

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault
resultYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.1.0

TDQS

A4.3/5.0
Behavior5/5

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

The description goes well beyond the annotations by explaining non-obvious behaviors: for_each spreads item dict keys as keyword arguments, results include identifying fields to disambiguate items, and exceptions do not abort the whole pipeline but become ok=False/error in the step result. This is exactly the kind of behavioral context an agent needs and the annotations do not provide.

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?

The description is dense but front-loaded with the core action. Every clause adds meaningful semantic detail, though the middle section is a long, complex sentence that could be broken into clearer bullet points. It is efficient given the complexity of the tool.

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

Completeness5/5

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

The description covers ordering, step construction, result naming, iteration over prior results, argument mapping, result disambiguation, and error handling. The presence of an output schema means return-value documentation is not required, and the description otherwise gives an agent everything needed to construct a valid pipeline correctly.

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

Parameters5/5

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

Schema description coverage is 0%, so the description carries the full burden for parameter semantics. It explains steps, block, args, save_as, for_each, item_arg, and the result shape in substantial detail, far exceeding the bare JSON schema definitions. It also clarifies subtle interactions like the '@name.field' reference syntax and keyword spreading.

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?

The description opens with a specific verb and resource: 'Runs a list of steps in order.' It then defines what each step contains (block, args, save_as, for_each), making the tool's purpose unmistakable. It is clearly differentiated from the sibling file/db/llm tools by its orchestration role.

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

Usage Guidelines2/5

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

No explicit guidance about when to use this tool versus alternatives, nor any when-not-to-use or exclusion criteria. The orchestration purpose is implied by 'Runs a list of steps in order,' but the description never tells an agent to choose this over calling individual blocks directly or using another tool.

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