Index a project

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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the safety profile is covered structurally. The description adds real behavioral value beyond that: it explains the incremental strategy (only new/edited/outdated files are embedded, deleted ones dropped) and that duplicates indexing is opt-in and persists across calls. It stops short of noting cost/duration or concurrency concerns for a long-running index build.

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?

Three tight sentences: purpose first, then the incremental/destructive behavior, then the one opt-in flag that has side effects on another tool. No filler, and the most decision-relevant fact is front-loaded.

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 4-parameter mutation tool with no output schema and annotations that already carry the safety hints, the description covers purpose, mutation semantics, and the one non-obvious flag. It is complete enough to invoke correctly; only return/status reporting and expected duration are unaddressed, which is minor given index_status exists.

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 path, force, duplicates, and extensions are all self-documenting in the schema. The description reinforces the duplicates parameter's cross-tool effect on find_duplicates, which is mild added meaning, but does not clarify force vs. default or extension-list persistence beyond what the schema says. Baseline 3 applies.

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+resource ('Build or refresh the semantic index of a project root') and immediately scopes what it touches. It is distinguishable from siblings like index_status (which presumably reports) and semantic_search (which queries) without opening any schema.

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 gives one concrete usage instruction — pass duplicates: true once to enable find_duplicates — which ties this tool to a sibling. However, it never says when to call this versus index_status (e.g., check status before reindexing) or when a full rebuild (force) is warranted over the default incremental behavior.

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