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 adds what matters beyond that: the return shape (id, title, url), the fact that results are summaries requiring a follow-up fetch for the sourced record, and the educational-not-medical-advice disclaimer. It does not discuss pagination behavior for the limit parameter beyond the schema's own maximum.

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 trigger condition in the first clause, then scope, then return/follow-up behavior — a sensible priority order. The long parenthetical inventory of example terms is somewhat dense but earns its place by showing the cross-domain reach in one pass.

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 read-only search with no output schema, the description supplies the essentials an agent needs: when to call it, what domains it covers, what comes back (id/title/url), and how to continue to the full record. Nothing critical is missing, though a note on result cap/paging behavior would round it out.

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 both parameters including example query values and the limit bounds. The description's contribution is mainly illustrating the breadth of searchable entity types (compounds, receptors, enzymes, conditions, trials), which adds a little meaning about what "query" accepts but largely overlaps the schema examples. Baseline 3 is appropriate.

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 all of Greencyclepedia") plus the scope it covers (compounds, receptors/enzymes, conditions with evidence grades, clinical trials), which is enough to distinguish it from the scoped siblings like search_compounds, search_conditions, and the get_* tools. An agent can tell this is the broad discovery search without opening any 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?

Gives an explicit when-to-use trigger: "Use when you do not know the exact name or id, or want to see what Greencyclepedia holds on a topic" — which implicitly contrasts with exact-lookup tools. It also provides a follow-up path ("pass an id to fetch for the full sourced record"). It stops short of naming the domain-scoped search siblings as explicit alternatives, so routing among search/search_compounds/search_conditions still requires inference.

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