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

Annotations already declare readOnlyHint, idempotentHint and non-destructive, so safety is covered; the description goes further by disclosing the return shape (summary, key topics, decisions, open action items, timestamp) and the newest-first ordering. That ordering detail matters for interpretation and is not in the annotations. It stops short of noting any truncation or empty-result behavior despite the 15-item cap.

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 with purpose, then usage triggers, then return contents, then the sibling exclusion — a logical order. The four quoted example utterances are slightly repetitive but each serves as a retrieval cue, so little feels wasted.

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 output schema, the description carries the burden of return values and does so well (summary, topics, decisions, action items, timing). Missing only edge-case framing — what happens with zero matches, and whether recall spans all companies when company is omitted — which the schema only partially addresses.

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%, including defaults and max for limit, keyword examples for query, and the list_companies pointer for company, so the baseline is 3. The description adds no parameter-level guidance of its own beyond implying topic filtering exists; naming when to prefer query over a higher limit would have raised this.

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 ('Recall what you and the user discussed in PAST conversations') and pins down scope: earlier sessions, including voice and video calls. It also explicitly separates itself from read_company_wiki ('curated durable facts, not the back-and-forth of past chats'), so an agent can pick between the two without opening either schema.

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 concrete trigger phrases ('what were we talking about last time?', 'remind me what we discussed') that map directly onto user utterances, and adds a hard rule: ALWAYS call this before saying you don't remember. The exclusion against read_company_wiki completes the when/when-not pair.

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