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

Annotations already declare a non-destructive write (readOnlyHint=false, destructiveHint=false, openWorldHint=false), and the description adds genuinely new behavior: the newest session is injected into brand context for any AI, and at 5+ sessions recurring themes are extracted and the brand context is enriched. It does not say whether repeated calls create duplicate sessions or overwrite, which is the main residual gap for a write tool.

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 the invocation trigger, then what is stored, then the downstream effect, then the exclusion — a logical order with no filler. Every sentence carries distinct information an agent can act on.

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 4-parameter, single-object write with no output schema, the description covers the trigger, the payload, the downstream consumption and the sibling boundary. It stops short of describing the call's return value (e.g., a session id the agent might want to reference later), which would round it out.

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 every parameter is already documented, and the description's mention of summary, decisions and next steps only restates what the schema says. The session_source parameter is never referenced in the description. Baseline 3 is appropriate since the schema carries the parameter burden.

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 (save/log a session) plus exactly what it writes: a summary of what was accomplished, key decisions and next steps. It explicitly contrasts with remember_brand_fact and, by implication, with the read-side siblings get_latest_session and list_sessions, so an agent can route correctly without opening a 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 an explicit trigger ('when the user asks to save or log this session, or wants the next conversation, in any AI tool, to pick up from here') and an explicit exclusion with the named alternative ('Do not use it for a standing brand fact; use remember_brand_fact for that'). Both the when and the when-not are present.

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