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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered; the description goes further by disclosing the auth model (identity resolved from JWT, "no server gate on this call"), the per-draft override via input.actorId, and field-level semantics such as mostRecentAt being null when there is no activity in the 14-day window.

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 and well-organized with nested bullets that make the response shape scannable. It loses a point for redundancy: the retrieveVia hint is explained in the contextBundle bullet and then restated almost verbatim under "Navigate using response fields."

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?

No output schema exists, so the description carries the full burden of explaining returns, and it does so for a nested contextBundle (recencyPointer fields, gap/contradiction counts) plus usage instructions. For a zero-required-parameter entry-point tool with a complex response, nothing essential is missing.

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%, so the schema already documents includeEvents; the description still adds decision-relevant meaning by naming the payload (up to 3 recent decisions per root domain) and the task shape that warrants it. It stops short of describing ordering or what "recent" means beyond the schema text, keeping it at 4 rather than 5.

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?

Opens with a specific role statement ("Primary orientation tool") and enumerates exactly what it returns: actor identity from JWT, workspace statistics, and suggested queries. An agent can distinguish it from engramic_search or engramic_topic because they are explicitly named as downstream navigation targets rather than alternatives.

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 explicit timing ("Call this at the start of every session") and an explicit when/when-not for the only parameter: includeEvents is for "review-shaped or resumption-shaped" tasks and "not for default orientation." It also routes to alternatives by mapping response fields to siblings (rootDomains → engramic_topic, suggestedQueries → engramic_search, retrieveVia → engramic_timeline).

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