datetime_day_of_week

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

No annotations are provided, so the description carries the full behavioral burden. It does disclose the return value's shape (a weekday name string) with a concrete example, which is useful, but says nothing about accepted input formats, timezone handling, or error behavior for unparseable dates.

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?

One front-loaded sentence with zero wasted words; the output format and an example are packed into a single clause.

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?

An output schema exists, so return values need no elaboration. But the critical input-format ambiguity remains unresolved across description, schema, and annotations, leaving a genuine gap for a date-parsing tool.

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% for the single parameter 'date_string', and the description only echoes it as 'a given date'. It doesn't specify the expected date format (ISO 8601? epoch? locale-dependent?), which is the one piece of information an agent actually needs to call this correctly.

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 ('Return') and resource ('weekday name') with an inline example ('Friday'), so an agent can distinguish it from siblings like datetime_week_number or datetime_format. However, it doesn't explicitly contrast itself against those siblings, 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?

No guidance on when to use this versus datetime_week_number, datetime_format, or datetime_parse, which all operate on dates. The agent must infer the selection criteria from tool names alone.

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