hours_by_day

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

With no annotations, the description carries the full burden; it does add a genuinely useful behavioral fact — the read:time_entries permission requirement — which no structured field provides. However it says nothing about default scoping (all users vs. one), date format expectations, timezone/boundary handling, or aggregation semantics, which are the traits an agent most needs here.

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?

A single compact sentence with the core purpose front-loaded and the permission caveat trailing. Nothing is padded.

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?

Placeholder.

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 0% across 4 parameters, so the description is the only place meaning could be added, and it adds almost none — it never mentions user_id, project_id, start_date, or end_date. The only hint is that hours are grouped by day, which the name already conveys.

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 resource and shape: per-day hours derived from time entries, plus the claim that it is the authoritative hours source. That distinguishes it from get_hours_summary, though the differentiation is left implicit rather than naming the sibling.

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 a soft steer via 'the authoritative hours source', implying this should be preferred over get_hours_summary, but no explicit when-to-use/when-not or conditions under which the other aggregation should be selected. Usage is implied, not stated.

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