Get one memory entry by key

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

Annotations already indicate readOnlyHint and idempotentHint. The description adds behavioral details beyond annotations: it specifies return fields (timestamps, ttl, tags, metadata) and the null result for missing/expired entries. No contradiction.

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?

Two sentences, front-loaded with key action, no redundant words. Every sentence adds value: the first states the core action, the second describes return values and edge case.

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 simple single-parameter tool with annotations, the description covers the main use case, return data, and critical edge case (null). The absence of an output schema is mitigated by describing return fields. Minor gap: no detail on pagination or limits, but not essential here.

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 covers the single parameter 'key' with description including case-sensitivity. Description adds 'Exact key lookup' but does not significantly augment parameter meaning beyond the schema. With 100% schema coverage, baseline 3 is appropriate.

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?

The description 'Exact key lookup' clearly states the specific verb and resource, distinguishing it from sibling tools like memory_search and memory_list. The mention of returned data (timestamps, ttl, tags, metadata) and the null case further clarify scope.

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?

The description implies when to use ('Exact key lookup'), suggesting use when the exact key is known. It does not explicitly state when not to use or list alternatives, but the context is clear enough for an AI to infer proper usage.

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