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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds that the search operates through the AI6 MCP reader plane and that results return ids for fetch, which is useful behavioral context beyond the annotations.

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?

The entire description is a single efficient sentence with no filler. It is front-loaded with the action and resource, and the fetch follow-up instruction earns its place.

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 one-parameter search tool with an output schema and read-only annotations, the description provides the essential workflow: search, get result ids, then fetch full text. It does not mention limits or failure modes, but the presence of an output schema and the simple scope make this adequate.

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% and the schema already documents 'query' as a natural language search string. The description adds no additional query-formatting or semantics, so the baseline of 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?

The description names a specific verb ('Search') and resource ('StackFast Brain knowledge'), and clarifies the read-only plane it operates on. It also distinguishes itself from fetch by telling the agent to use fetch with the returned result id for full text.

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?

The description clearly says to use fetch with a returned result id for full text, giving an explicit follow-up action and signal that search results are summaries/ids. It does not enumerate when not to use search versus the many other search-like siblings, but the specific resource scoping makes the intended use unambiguous.

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