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

Adds substantial context beyond the read-only/idempotent annotations: the default filter is servers whose last check completed initialize + tools/list without a key, results are ranked by relevance then tool count, and there's an explicit caveat that this is an automatic check, not a hands-on test or safety review. That caveat is exactly the kind of limitation an agent needs before trusting results.

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 dense sentences, front-loaded with what is searched and what comes back, with no filler. The middle sentences are information-heavy but each carries distinct value (match fields, default filter, return contents, caveat).

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?

No output schema exists, so the description's summary of returns (endpoint URLs, tool names, check dates) fills that role. Combined with the default-filter and caveat statements, an agent has everything needed to call this correctly and interpret results.

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 coverage is 50%, with sort and limit undocumented structurally, but the description compensates by explaining the default usable_without_auth filtering and the default ranking order (relevance, then tool count), which maps to the sort enum. It doesn't spell out the non-default sort values or the limit cap, leaving a small gap.

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?

States a specific verb and resource ('Search Agent Tested's live map of hosted MCP servers from the official MCP Registry') and the exact scope of the search fields (name, title, URLs, tool names). This clearly separates it from siblings like search_tools, get_tool and list_registry_checks.

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?

Explains the selection condition well: it finds servers an agent can connect to right now, and notes that usable_only=false widens to servers needing sign-in or failing. It doesn't explicitly name a sibling alternative, which keeps it below a 5, but the when-to-use context is unambiguous.

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