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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety is covered. The description adds genuinely useful behavior: what each match contains (name, description, input schema, hints, scope) and the non-obvious workflow requirement that tools absent from tools/list must be invoked via call_tool. No rate limits or ranking behavior are mentioned, which keeps it below a 5.

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?

Front-loaded with the core definition, then the coverage list, then the follow-up instruction and example — a sensible order. The enumeration of unlisted capability areas is long, but each item materially widens the agent's sense of what is findable here, so it mostly earns its space.

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?

For a two-parameter discovery tool, the description covers what it searches, its scope past tools/list, what a result contains, and how to execute an unlisted match. Even though an output schema exists, the description's summary of the return shape makes the workflow self-contained.

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 100%, so both parameters are already documented (limit 1–20 default 5, query in plain words). The description's example "{ "query": "rename a folder" }" still adds value by demonstrating the natural-language phrasing expected for query, which is a subtlety the schema alone leaves ambiguous.

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 ("Full-text search over every Prubex tool") and immediately scopes it beyond tools/list to drafts, labels, folders, profiles, etc. That scope statement clearly separates it from siblings like mail_search, docs_search and profiles_list, which search content rather than tool definitions.

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?

Explicitly says "Use it when no listed tool fits the task," which is a clean when-to-use condition, and names the follow-up path ("run unlisted ones with call_tool"). The agent knows both when to reach for this tool and what to do with the results.

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