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

Annotations already cover readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is settled. The description goes beyond them with concrete behavioral limits: a 100-observation cap, explicit retention windows, gaps in intermediate observations, and the caveat that observations do not prove delivered notifications. 'Does not change the search' is slightly redundant with the read-only hint.

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?

Two tight sentences with the core action front-loaded, followed by the retention and interpretation caveats. Every clause adds decision-relevant information; nothing is padding.

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 single-parameter read tool with an output schema and four annotations, the description supplies the remaining needed context: scope, cap, retention caveats, and interpretation limits. Only the routing context against sibling observation tools is thin.

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% for the single id parameter, including where to obtain the UUID, so the schema carries the burden. The description reinforces the workspace/ownership constraint but adds no format or validation detail beyond the schema's baseline 3.

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 ('read the latest 100 retained change observations for one saved search') with an explicit scope of workspace ownership. An agent can tell this is a change-history read rather than a search execution. It does not explicitly distinguish itself from plausibly similar siblings such as exclusion_changes or freshness, so it stops short of 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?

Usage is implied by the retention/observation framing, and 'Does not change the search' signals read-only intent, but there is no explicit when-to-use guidance and no named alternative (e.g., vs exclusion_changes or freshness). The agent is left to infer the selection criteria.

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