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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered by structured data. The description's own additions are modest: 'deterministic' largely restates idempotentHint, and the only genuinely new disclosure is that it returns both a structured object and a short text version. No auth, rate-limit, or scope caveats beyond what annotations supply.

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 short sentences, front-loaded with what it returns and scoped by what is included; the usage hint comes last. Every sentence adds something except the minor 'read-only' restatement of annotations, which is not enough to penalize.

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 no parameters and no output schema, the description adequately covers the return shape (structured object plus short text) and the safety profile is handled by annotations. Complete enough to invoke correctly, though it does not say how large the summary is or whether it can be empty for new users.

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?

The tool takes zero parameters, so the schema carries no semantic burden and there is nothing for the description to disambiguate. Baseline is 4 for a parameterless tool.

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 a specific verb and resource ('Returns a compact summary of what the user has saved about themselves') and enumerates the contents (preferences, facts, working style, projects, to-dos). It is clearly distinguishable from raw-retrieval siblings like memory_get or memory_search, though it never names an alternative to route against.

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 a concrete when-to-use context: 'Useful before writing something for the user, to follow their stated style.' That is a real trigger rather than implied usage, but it offers no exclusions and does not point to any of the ~20 sibling memory/plan tools when this one is the wrong choice.

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