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

Beyond the readOnly/destructive annotations, it discloses billing behavior (space infrastructure charged to the owner against weekly coverage, then Credits), that the call never launches an agent, that reads do not create a Personal space, and that sources/skills are untrusted reference data rather than permissions. These are non-obvious side-effect and trust-boundary facts an agent cannot get from structured fields.

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?

It is front-loaded with the scope statement, which is good, but several sentences ('Updates and removal require the exact current version', 'skills share this knowledge authority') describe sibling-tool behavior rather than this read operation and dilute the payload. Dense, but not every sentence earns its place in a search-tool description.

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?

An output schema exists so return-value explanation is not needed, and the safety/trust profile is well covered. However with zero schema description coverage on 5 parameters, the definition leaves an agent guessing about query construction, pagination and history semantics — a material gap for a search tool.

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 0% across 5 parameters, and the description only implies what space_id means (defaults to Personal). It says nothing about query syntax or matching semantics, limit bounds, cursor usage, or what include_history changes — the highest-value parameter behavior is undocumented.

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 first sentence gives a specific verb ('Search'), a specific resource (entries / knowledge) and a scope (one currently authorized private Space, defaulting to Personal). An agent can tell it apart from private_knowledge_get or private_space_full_history_search by scope, though the description never names those siblings.

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?

It explicitly routes one case — 'Reads do not create Personal; use private_space_personal for explicit first-use setup' — which is genuine when-to-use guidance. But it never clarifies how this differs from private_knowledge_list, private_knowledge_get, or private_space_full_history_search, so the main selection decision among siblings is left implicit.

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