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

Annotations already declare readOnlyHint=true, so the agent knows this is safe to call. The description adds useful context about historical scope and index comparison, but does not disclose output shape, default window behavior, or truncation semantics; those are partly covered by schema parameter descriptions.

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 a single compact sentence that front-loads the core idea and includes the outcome comparison. There is no filler or repeated schema information.

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 read-only tool with 5 optional parameters and no output schema, the description gives enough orientation to understand the intent, and schema documents the parameters. However, it does not clarify what the response contains beyond 'what worked and what didn't', and it does not mention any rate limits or pagination beyond what the limit parameter hints at.

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 parameter descriptions already explain defaults, precedence (sinceIso vs days), canonicalization, and hitting behavior. The description adds no parameter-level detail beyond what the schema provides, 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?

The description names a specific resource (old alert outcomes), the action (settlement/evaluation), and the comparing basis (index), so an agent can tell it is about historical alert performance rather than a generic listing. It does not explicitly differentiate from similar siblings such as get_my_alert_performance or historical_event_hit_rate, which keeps it from a 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?

The phrase 'dawnych alertów' and 'na tle indeksu' implies this is for retrospective alert evaluations, but there is no explicit when-to-use or exclusion like 'use get_my_alert_performance for user-level performance'. Usage context is inferable yet not stated.

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