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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful behavior beyond that: results are ids intended for `fetch`, and the corpus is a curated closed set rather than the open web. It says nothing about result limits, ranking, or empty-result behavior, so with annotations carrying safety it lands at baseline-plus.

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?

Scope is front-loaded in the first clause and the routing rule follows immediately; the long topical enumeration earns its length by delimiting the domain. Only the domain list is dense enough to skim past, and nothing is redundant with the schema.

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 one required parameter and no output schema, the description covers the two things an agent needs: what corpus is searched and what comes back (ids for `fetch`). No output schema exists, so the return-value handoff note is doing necessary work. Minor remaining gap is absence of guidance on what to do when results are empty or ambiguous.

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% and the single `query` property already documents itself with worked examples ("casing failure above 400 C", "magma Krafla"). The description adds no syntax, phrasing, or length guidance beyond the schema, so the baseline 3 applies.

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 the verb (search) and resource precisely, then enumerates the concrete corpora covered: the Superhot Well Registry, projects, field lessons, RockLab models/datasets, open problems, and the research library. That is far more specific than the generic name 'search'. It stops short of distinguishing itself from the sibling search_wells and search_library, so an agent must still infer the boundary.

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 it first for any question about..." is an explicit default-entry routing rule, followed by a concrete topical list (superhot rock, supercritical >374 C, EGS, well failures, projects, firm power for AI). It also names the downstream tool via "Returns ids to pass to `fetch`". It does not state when to prefer the narrower sibling searchers instead.

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