rails_search_docs

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

The annotations already declare readOnly, idempotent, non-destructive and openWorld, so the safety profile is covered. The description adds real value beyond that by disclosing that fetch:true reaches out to GitHub and is cached for 24 hours, which is the kind of network/state behavior an agent needs. It stops short of describing result shape or what happens on a cache miss.

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

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

Four short, front-loaded sentences: scope first, then when-to-use, then query/filter examples, then the fetch behavior. Nothing is padded, though the filter enumeration edges toward repeating the schema's enum.

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

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

With no output schema, the description still conveys what comes back ("matching topics", and full content when fetch is true), which is the key return-value context. It omits the limit default and result ordering, but those are documented in the schema.

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

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

Schema description coverage is 100%, so the schema already documents query, source, limit and fetch completely. The description's example query string and source filter values largely restate what the schema provides, adding only mild emphasis. Baseline 3 is appropriate given the schema does the heavy lifting.

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

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

The description uses a specific verb ("Search") against a precisely delimited resource: "a bundled index of the Rails guides and the Turbo, Stimulus and Hotwire Native handbooks." By naming the exact corpora, it implicitly distinguishes itself from the corpus-agnostic sibling rails_search_code and from project-introspection tools like rails_get_schema.

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

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

"Use when: you need to reference Rails conventions, API details, or best practices" gives an explicit trigger condition. However, no negative guidance or named alternative is offered — e.g. it never says to use rails_search_code for project code instead — so an agent must infer the boundary.

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