index_patch

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

With no annotations, the description carries the full burden and does reasonably well: it discloses the optimistic-concurrency requirement (if_match), a refusal condition with its error code, and the return payload (path, content_hash, replacements, findings). It omits permission/auth needs and whether edits are atomic, leaving some behavioral gaps.

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 compact sentences that front-load the analogous tool and the target resource, then cover prerequisites, exclusions, and return values. Dense but every clause earns its place; the 'Like concept_patch' dependency is the only minor cost.

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 no annotations, no output schema, and 29% schema coverage, the description covers routing, concurrency, error handling, and returns, but leaves several parameters (edits shape, reason, replace_all) under-explained. Adequate but with clear 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 coverage is only 29%, so the description must compensate. It documents if_match's origin and defers edit-form semantics to concept_patch ('same edit forms'), but says nothing about edits structure, replace_all, or reason beyond the schema's brief hints. Partial compensation only.

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 (patch) and resource (root or Map/Journal curated index.md) and explicitly distinguishes itself from concept_patch for expanded-concept indexes. The reliance on 'Like concept_patch' means the agent must know what that sibling does, so it is clear but not fully self-contained.

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?

Names the prerequisite (if_match from index_get with_hash) and the exclusion case (an expanded concept's own index.md is refused with expanded_index), routing to concept_patch. Clear context and a named alternative, though it doesn't spell out the full when-to-use conditions for every index type.

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