project_update_part

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

With no annotations, the description carries the full burden and does disclose the key side effects: the part stays in place in the toml, its documents are retained rather than recreated, and project_sync handles relocations caused by layout. It also states the return payload ('Gives the part and its documents'). It does not mention permissions, error/atomicity behavior, or what happens on partial conflicts (e.g. duplicate MPN with differing manufacturer).

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?

Purpose is front-loaded in the first clause, and the remaining sentences carry real information about preservation and sync. The sentence about project_sync moving a copy 'when the layout gives it a different subfolder' is slightly elliptical and takes a moment to parse, but nothing is wasted.

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 7-parameter mutation tool with an output schema and full schema coverage, the description supplies the crucial non-schema context: in-place semantics, copy preservation, and the sync interaction. Given the output schema exists, it need not describe return values in detail. The absence of any annotation coverage leaves error/authorization behavior unstated, which is the main remaining gap.

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 every parameter including the empty-means-no-change semantics and the category null/empty distinction is already documented in the schema. The description only restates the four mutable fields at a high level and adds no syntax, format, or edge-case guidance beyond that.

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 opens with a specific verb and object ('Change a part of the user project in place') and enumerates the mutable attributes (MPN, base part, category, manufacturer). It distinguishes itself cleanly from project_remove_part/project_add_part by contrasting in-place editing with delete-and-recopy.

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?

It names the sibling alternatives (project_remove_part, project_add_part) and explains why you would pick this one instead: the part keeps its position in datasheet-lens.toml and its document copies. It also points to project_sync as the follow-up for relocating a copy. There is no explicit 'do not use when...' exclusion, but the contrast gives a clear selection signal.

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