String Utility Belt

List utilities

list_utilities

Read-only

Search a bundled catalog of string-transformation utilities by keyword or category to find matching IDs before describing or running them.

Instructions

Search the string-transformation utilities this server can run (247 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

TableJSON 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

TableJSON 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

A4.9/5.0

Behavior5/5

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

Annotations only declare readOnlyHint and openWorldHint=false; the description goes well beyond them, disclosing that it reads a bundled catalog with no network access and no rate limit. It also documents the no-paging behavior and the remedy when `total` exceeds returned items, which is real operational context.

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 it searches, then return shape, then the call sequence, then edge cases. It is longer than average but every clause adds a distinct, actionable fact with no restatement of the title or schema.

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?

An output schema exists, yet the description still names the return shape and the paging caveat, and it covers filtering, failure behavior, and follow-up calls. Nothing an agent needs to invoke this 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 per-parameter meaning is already carried by the schema and the baseline is 3. The description adds non-schema value anyway: the AND semantics when `category` and `query` combine, the instruction to source category values from `categories`, and the limit-raising workaround.

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') plus scale and category coverage, so the agent immediately knows this is a catalog search, not an execution tool. The sibling relationship to describe_utility and run_utility is made explicit in the same breath.

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 call order ('Use this first to find an id, then call describe_utility for its exact parameters before run_utility') and an explicit when-to-omit condition ('omit both to browse the whole catalog'). It even pre-empts a failure mode by telling the agent to take a category from `categories` since unknown categories match nothing.

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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