String Utility Belt

List utilities

list_utilities

Read-onlyIdempotent

Search or browse the server’s string-transformation utility catalog by keyword or category, then use the returned IDs to describe and run the right utility.

Instructions

Search the string-transformation utilities this server can run (248 total, across categories like Encoding, Hashing, Ciphers, Compression, Data Formats, Analysis, Generators and more). Returns {items: [{id, name, category, description}], total, categories}, best matches first. Use this first to find an id, then call describe_utility for its exact parameters before run_utility. category and query combine (a utility must match both); omit both to browse the whole catalog. A category that does not exist matches nothing rather than failing, so take one from categories. There is no paging: when total exceeds the items returned, raise limit or narrow the query. Reads the bundled catalog only: no network access and no rate limit.

Input Schema

Name	Required	Description
`limit`	No	Maximum number of results to return (default 50, max 500).
`query`	No	Search words, matched case-insensitively against id, name, tags, aliases and description; every word must match somewhere, in any order (e.g. "encode url", "sha256", "uppercase").
`category`	No	Category to filter to (case-insensitive), e.g. "Encoding" or "Hashing".

Output Schema

Name	Required	Description
`items`	Yes	Matching utilities, best first, up to `limit`.
`total`	Yes	How many utilities matched before `limit` was applied.
`categories`	Yes	Every category name, for filtering.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.8.0Oct 17, 2026

TDQS

A4.4/5.0

Behavior3/5

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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description still adds real value beyond that: no network access, no rate limit, no paging, best-match ordering, and that unknown categories silently match nothing rather than erroring. It even explains the recovery path when total exceeds items returned.

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?

Front-loads what the tool searches and its result shape, then workflow, then filter semantics, then edge cases. Every sentence introduces new information; none restates the name or the schema.

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?

Covers the full call path from discovery to execution, filter interaction, pagination behavior and environment constraints, which is complete for a three-optional-parameter listing tool with an output schema. Nothing an agent needs in order to call it correctly is missing.

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 baseline is 3, but the description adds conjunctive AND semantics between category and query and tells the agent to source category values from the returned `categories` list. It also hints at limit as the remedy for truncated results, meaning that goes beyond the schema's bare maximum.

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 ('Search the string-transformation utilities this server can run') and immediately scopes it with the catalog size and category list. It is unambiguously a discovery tool, clearly distinct from describe_utility and run_utility, which it names.

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 ordered workflow: use this first to find an id, then describe_utility for parameters, then run_utility. It also specifies when to omit filters (browse the whole catalog) and how filters combine (a utility must match both).

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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