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

Annotations already declare readOnly/idempotent/non-destructive, yet the description still adds substantial context beyond them: the since/until filtering semantics, exponential decay via half-life, an error contract (returns {error: ...} rather than raising a protocol error), and the retry-safety guarantee. The premium licensing constraint is also disclosed.

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 purpose, then semantics, then a request/response example, then the error and idempotency contract — every block is purposeful. The inline JSON example of input and return payload is slightly redundant given the output schema exists and could be compressed, but it does show the dropped/decayed counters concretely.

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 3-parameter, nested-graph tool with a premium gate, the description covers purpose, filtering semantics, decay, error behavior, and retry safety. Return shape is partly described despite an output schema existing, so nothing an agent needs to call or recover from a call is missing.

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 real meaning: a worked example showing as_of as a concrete ISO date and half_life_days = 180, plus the explanation that a two-year-old belief should not weigh the same as last week's, which conveys the intent of decay. It does not clarify that half_life_days=0 disables decay without leaving that to the schema.

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: viewing the memory graph as of a given date, with optional age-based confidence decay. It also names the sibling it is not (graph_diff) and the condition that separates them, so an agent can route without opening any 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 positive trigger ("Use when the answer depends on when you ask") and an explicit exclusion pointing to the correct alternative ("Not for what changed between two points - that is graph_diff, which does not need dates at all"). It also flags the PREMIUM license requirement up front, which is a gating condition for use.

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