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

Annotations already cover read-only, idempotent, closed-world, non-destructive semantics, so the bar is low. The description still adds real value by disclosing the conditional 'stale flag' behavior when topic memories changed after the summary was written — output semantics not derivable from 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?

A single front-loaded sentence with zero waste: what is returned comes first, the notable staleness caveat second.

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 read-only, two-parameter tool with no output schema, the description covers the essential return nuance (summary plus stale flag). It omits what happens when no summary exists and defers the brain default entirely to the schema, so it is strong but not exhaustive.

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 both parameters (brain defaulting to the active brain, concept as the topic name). The description's '(concept)' restates what the schema says, so it adds little beyond the schema baseline.

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 ('Returns') and resource ('the stored summary of one topic'), and the parenthetical '(concept)' maps user vocabulary to the parameter name. It implicitly distinguishes itself from the write-side sibling topic_summary_set by being a retrieval, but never names an alternative explicitly.

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?

Usage is only implied by the read verb — an agent can infer you call this to fetch a topic's summary, but the description gives no when-to-use guidance, prerequisites, or alternatives (e.g. recall, memory_search, topic_summary_set).

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