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

With no annotations, the description carries the transparency burden. It clearly states the action (downgrade), the condition (older than max_age_days), and the direction (GREEN to YELLOW). It does not disclose the scope when entity_id is omitted or whether the operation is idempotent, but the core behavior is transparent.

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 extremely concise: two sentences, no filler. The first sentence states the action, the second explains the trigger and schedule. Every word contributes value.

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?

The tool is simple, but the description leaves ambiguity about the scope when entity_id is not provided (does it process all entities?), and token_symbol is not explained. It also doesn't clarify behavior for already-yellow evidence. Given the lack of output schema and annotations, these gaps make it slightly incomplete.

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%, so baseline is 3. The description adds meaning to max_age_days by tying it to the downgrade condition. However, it provides no additional insight into entity_id or token_symbol beyond the schema's minimal descriptions.

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 states a specific verb ('Expire') and resource ('stale evidence'), then elaborates with a concrete state transition ('GREEN→YELLOW') and condition ('older than max_age_days'). This clearly identifies the tool's function and distinguishes it from siblings like readiness_check or health_check.

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?

Provides explicit usage frequency ('Run daily'), which gives clear operational context. However, it does not mention alternatives or when not to use the tool, so it misses the 'when-not' aspect.

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