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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context beyond annotations: it is free with no coin cost, displays a monthly calendar view, and shows event icons with details when days are clicked.

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 front-loaded with the main purpose and remains compact. Some UI-specific phrasing ('when clicking on days') is less relevant for an agent, but the text is not bloated.

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 low-complexity, read-only view tool with rich annotations and fully documented parameters, the description covers what the diary contains and how it is presented. The lack of an output schema is partially offset by the calendar-view description, though return-value structure is not detailed.

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 the two parameters (year, month) are fully documented with defaults in the schema. The description adds no parameter-specific meaning, so the baseline of 3 is appropriate.

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 uses a specific verb ('View') and resource ('personal learning diary calendar'), then enumerates the activity types shown: logins, learning sessions, achievements, coin transactions. This distinguishes it from sibling tools like my_profile or my_courses, which cover different data.

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 personal diary framing and the note that it is free (no coin cost), but there is no explicit guidance on when to use this instead of alternatives such as my_profile, nor any exclusions. An agent must infer the appropriate context.

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