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

Annotations already convey that this is a non-read-only, non-destructive, idempotent mutation, so the description does not need to restate those. It adds a useful list of updatable fields but does not clarify partial-update semantics, such as whether omitted fields are preserved or whether a missing entry is created.

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 front-loaded sentence that states the operation and the core fields without filler. Every phrase contributes to understanding what the tool does.

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?

Schema fields, defaults, and annotations cover much of the necessary context, and no output schema is present. However, with seven optional parameters and no required fields, the description should clarify partial-update behavior and what happens when only some fields are supplied; this ambiguity is material for correct invocation.

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 all seven parameters are already documented in the input schema. The description mostly restates parameter names and ranges without adding new meaning, and it omits focus_completed entirely, though the schema covers it.

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 and resource ('Update the daily journal') and enumerates the concrete fields being set (mood, energy, focus text, notes), which clearly distinguishes it from read-oriented siblings like get_daily_entry. It is immediately apparent what this tool operates on and what it changes.

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?

There is no explicit guidance on when to use this tool versus alternatives such as get_daily_entry, nor any mention of prerequisites or conditions (e.g., the entry must already exist, or that this is for modifications only). Usage is left entirely to inference from the verb 'Update'.

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