Remember a fact

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

Annotations already declare idempotentHint=true and destructiveHint=false; the description adds genuinely new behavior: exact duplicates in the same namespace are never double-stored, the existing memory is returned with deduplicated=true, new tags are merged and reported in merged_tags, and tags are case-insensitive. This is exactly the extra context annotations cannot carry, and it is consistent with them.

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 core action, then trigger guidance, then edge-case semantics, then return shape. Every sentence earns its place, though the return-value paragraph is slightly verbose given it repeats field names that the caller can discover at runtime.

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?

There is no output schema, so the description correctly takes on the burden of describing the response (id, content, namespace, tags, timestamps, deduplicated, merged_tags, message). Combined with dedup, namespace scoping, and tag case rules, an agent has everything needed to call and interpret this write tool.

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 baseline is 3, but the description adds meaning the schema does not: dedup is scoped to 'same content in the same namespace' (clarifying namespace semantics) and tags are case-insensitive with merge behavior on duplicates. No syntax or format gaps remain.

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: 'Store a fact in persistent memory', with the scope qualifier 'so it survives across sessions'. It is clearly distinguishable from retrieval siblings like recall in spirit, but it never names an alternative explicitly, so it stops short of a 5.

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?

'Use this whenever you learn something worth keeping' plus concrete examples (user preferences, project decisions, environment quirks, follow-ups) gives a clear trigger. It omits any when-not guidance or named alternative (update_memory, forget), which keeps it out of 5 territory.

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