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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so safety and side-effect behavior are covered. The description adds only the mild scope hint that the memory was 'stored earlier' by the caller. Nothing is said about behavior when the key is absent or about what the lookup returns.

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?

One short sentence, front-loaded with the action and the addressing mechanism, with no padding. It is appropriately sized for a single-parameter read tool, though it is terse enough to leave the usage question open.

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 trivial one-parameter read with full schema coverage and annotations carrying the safety profile, the definition is minimally sufficient; no output schema exists so return values need not be explained. The notable gap is failure behavior for a missing or expired key, which an agent would want to know before calling.

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 single 'key' parameter is fully documented. The phrase 'by its key' adds no format, casing, or scoping detail beyond the schema, so the baseline 3 applies.

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 (recall) and resource (a memory), plus the addressing mode (by its key), so the agent knows this retrieves a single stored item rather than enumerating the store. It does not name the sibling it competes with (list_memories) the way an ideal definition would, so it stops short of 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?

There is no explicit when-to-use or when-not-to-use guidance. With list_memories sitting right beside it, the definition never says to use recall for a known key and list_memories when the key is unknown, leaving the routing decision to inference from the word 'key'.

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