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

Annotations already declare idempotentHint=true and the read/write profile, so the safety burden is light. The description adds real value beyond that by explaining the upsert semantics ('calling again for the same date corrects it') and hinting at output ('Says when the target is reached').

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?

Front-loaded with the core purpose, then example, correction rule, and output hint. Short and largely waste-free, though the three clauses could be tightened slightly.

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 simple two-parameter write tool, the description covers purpose, correction semantics, and return behavior, compensating for the absent output schema. Only minor gaps (units, relation to goal definition tools) remain.

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 coverage is 50% (date is documented with format and timezone, value is bare). The example 'I now have 4 customers' clarifies what value means as an absolute current count, but the description does not resolve remaining ambiguity such as units or whether deltas are accepted.

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 (record the current value of the goal metric) and grounds it with a concrete example. It is clearly distinguishable from sibling tools like set_goal or get_goal, which handle the goal definition rather than progress values.

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 note 'One value per date: calling again for the same date corrects it' implies when to call and how to fix mistakes, but there is no explicit guidance on when to use this versus set_goal or how it relates to check_goal_draft. Usage is implied rather than stated.

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