proj_scan

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavior: incremental mode re-indexes only files whose mtime changed. It does not disclose re-index cost, whether the index persists across calls, or whether a full scan is needed on first use.

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?

Two tight sentences, front-loaded with the core action and followed by the incremental-mode detail. Nothing is padded, though the parenthetical file-type list is dense and the second sentence could be clearer about what triggers the mtime check.

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 structure need not be explained. However, for a tool with an unexplained optional root parameter and many proj_* siblings, the description omits whether scanning is a prerequisite step and how it relates to proj_list/proj_search, leaving meaningful gaps.

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%, so the description must carry the load. It does explain incremental well ('re-indexes only files whose mtime changed'), but the root parameter is never mentioned, and its null default leaves it unclear whether null means the currently open solution or the working directory.

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 ('Index the project tree') and enumerates the artifact types it covers (.sln/.tsproj/.plcproj/.TcPOU/.TcDUT/.TcGVL/.TcIO), so the agent knows exactly what is being parsed. It does not however distinguish itself from siblings like proj_list, proj_search, or proj_changed, leaving the agent to infer the relationship.

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 that incremental=true is 'fast after XAE saves' implies when the incremental mode is appropriate, which is useful situational guidance. There is no explicit statement of when to run proj_scan versus proj_search/proj_get_code, nor whether a scan is a prerequisite for those tools.

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