Projects Update Assignment

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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false, openWorldHint=true), so the description only needs to add context. It adds the set of mutable fields, which is useful, but stays silent on the critical mutation semantics: whether omitted fields are left unchanged (which the all-null-default schema strongly implies) and why a non-idempotent update behaves that way.

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 front-loaded sentence with no filler, and the resource/action lead the sentence. It is only penalized in that its brevity leaves the gaps noted above unaddressed rather than that it wastes words.

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 explanation. But for a non-idempotent mutation over 7 undocumented parameters, the description omits partial-update semantics, the required assignment_id, and the note field, leaving an agent materially under-informed to call it correctly.

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 7 parameters, so the description carries the full burden. It loosely maps 'dates', 'allocation percentage', and 'hours' onto start_date/end_date, percent, and the three distinct hour fields (fixed_hours, hours_per_day) without disambiguating them, and it never mentions assignment_id (the sole required identifier) or note, which is silently updatable.

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?

Names a specific verb (Update) plus resource (assignment) and enumerates the mutable field groups (dates, allocation percentage, hours), so an agent knows what it does. However, it does not distinguish itself from siblings like projects_update_project, projects_update_project_phase, or projects_update_assignment_subtask, all of which follow the same naming pattern.

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 statement of when to use this tool versus alternatives, no prerequisites (e.g., assignment must exist / permissions), and no mention of the read counterpart projects_get_assignment for inspecting current values before mutating. Usage must be entirely inferred from the name.

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