Read a specific chunk of an indexed document by providing its document ID and chunk index, enabling access to large Markdown or PDF files in parts.
Reads a chunk of an indexed document (by chunkIndex).
| Name | Required | Description | Default |
|---|---|---|---|
| docId | Yes | ||
| maxChars | No | ||
| chunkIndex | No |
Changes observed during successful MCP inspections.
v0.0.0-devDoes the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden of behavioral disclosure. It states that reading occurs, but does not explain chunk indexing semantics, behavior when chunkIndex is omitted or out of range, whether results are capped by maxChars, or what the response looks like. These are significant gaps for a tool with no output schema.
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 a single, direct sentence with no filler or redundancy. 'Reads a chunk of an indexed document (by chunkIndex)' conveys the core operation efficiently and the key selection mechanism 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 tool with no annotations, no output schema, and three parameters with zero schema descriptions, this one-liner is insufficient. It does not explain chunk semantics, the role of maxChars, required preconditions like an existing index, or the return structure. An agent would need to guess or inspect external documentation to invoke it correctly in non-trivial cases.
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 compensate for the schema's lack of explanatory text. It only clarifies chunkIndex; docId and maxChars are left to inference from their names and schema constraints. The agent gets no explanation of how maxChars interacts with chunking or what docId refers to.
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 identifies the operation (reads) and the target (a chunk of an indexed document, selected by chunkIndex). This distinguishes it from sibling tools like lexomni_buildIndex, lexomni_searchDocs, and lexomni_writeNote, which have different verbs and resources.
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?
No guidance is given about when to use this tool or what prerequisites exist, such as 'the document must first be indexed via lexomni_buildIndex'. There is no mention of alternatives or exclusions, leaving the agent to infer usage context from the word 'indexed'.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.