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

Annotations already cover the safety profile (readOnlyHint, destructiveHint=false, openWorldHint=false), so the bar is lower, and the description still adds real context: results arrive pre-formatted as text, include graph neighbours, and health-tagged data is privacy-gated behind a user setting. It does not disclose truncation behaviour tied to maxChars or what happens when no passages match, which keeps it from 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?

Three sentences, each doing distinct work: what is built, when to prefer it over a sibling, and the privacy caveat. The purpose statement is front-loaded and nothing is repeated from the annotations or 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?

An output schema exists, so return values need no explanation, and the privacy gating plus the search-vs-recall routing are covered. The gap is the four undocumented tuning parameters — for a memory-retrieval tool, the agent has no guidance on how `depth`, `limit`, and `maxChars` should be set, which is a real usability hole.

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 0% across four parameters, so the description carries the full burden and largely fails: `depth`, `limit`, and `maxChars` are never mentioned, leaving the agent to guess at graph traversal depth, result count, and output size trade-offs. Only `query` is obliquely implied by 'a question'.

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?

Specific verb and resource: 'Build a context block from the user's CortexPlus memory', with the content spelled out as 'the passages that answer a question plus their graph neighbours, already formatted as text'. It also implicitly separates itself from the sibling `search` tool by describing a different output shape (a ready-to-use text block vs. raw search hits).

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 names the alternative: 'Prefer this over search when you intend to answer from the user's memory', giving both the preferred tool and the selecting condition. It also documents a conditional exclusion (health/`saude` data only when the user has enabled AI sharing), so the agent knows when content will be missing.

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