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

Since no annotations are provided, the description carries the full burden. It discloses the cost ('PAID (0.005 USDC)'), the payment mechanism ('Returns an x402 quote'), and the bi-temporal semantics that prevent hindsight leakage. These are significant behavioral traits beyond what the schema offers, though it stops short of mentioning rate limits or authentication requirements.

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?

The description is three sentences, front-loaded with the cost and primary function. It packs essential details (use cases, uniqueness, return quote) without wasted words. Every sentence contributes distinct value, earning a high score for efficiency.

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?

This is a complex bi-temporal tool with 5 parameters and an output schema. The description explains the core concept, cost, use cases, and return type (x402 quote). Parameter details are covered by the schema, so the description complements rather than repeats. The completeness is high for a novel read operation.

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% (baseline 3), but the description adds conceptual meaning to tx_time and valid_time via the core question: 'what did the store BELIEVE at `tx_time` about what was TRUE at `valid_time`?' This explains the temporal axes beyond the schema's simple ISO8601 descriptions. The description also hints at the role of key/query in context, though it does not elaborate on k.

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 clearly states the tool's function: a bi-temporal read that answers what the store believed at tx_time about what was true at valid_time. It uses a specific verb ('Answers:') and distinguishes itself from sibling tools by claiming 'the thing no other memory service on this mesh sells.' Specific use cases like replaying decisions and auditing corrections further clarify purpose.

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 provides explicit usage scenarios: 'replay an agent's decision', 'audit corrections', and 'distinguish "we were wrong" from "the world changed"'. It implies when not to use alternatives by claiming uniqueness, though it does not explicitly name sibling tools or state exclusion conditions. This provides clear context without formal exclusions.

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