index_sessions

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

The description fully discloses behavioral traits beyond annotations: it states that the tool mutates the index (consistent with readOnlyHint=false, destructiveHint=false), is idempotent (aligns with idempotentHint=true), and explains the skip/force logic. It also specifies the return JSON structure, which is not provided by an output schema. No contradictions with annotations.

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?

The description is three sentences covering what, behavior, and output. It is front-loaded with the main purpose, uses concise language, and contains no redundant phrases. Every sentence adds value.

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?

Given the tool's complexity (indexing sessions, conditional behavior, idempotent mutation) and the lack of an output schema, the description provides sufficient context: it explains the indexing target, the force parameter effect, idempotency, and expected return format. The sibling set includes 'search_sessions', which complements this tool, and the description positions it appropriately.

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 coverage is 100%, so the baseline is 3. The description repeats the default values ('current project' for project_root, 'false' for force) already in the schema. It does not add new semantic context beyond restating schema descriptions. The description is adequate but does not compensate for the lack of additional parameter guidance.

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 clearly states the verb 'Index', the resource 'conversation content from sessions', and the purpose 'for cross-session search'. It specifies the source (Claude Code / Claw Code sessions) and the mechanism (stores chunked messages in FTS5), making it distinct from sibling tools like 'search_sessions'.

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 description explicitly says 'Use before search_sessions', providing a clear usage context. It also explains the default behavior (skips already-indexed unless force=true) and notes idempotency. However, it does not mention when NOT to use this tool or describe alternatives.

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