read_file_chunk

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so safety is covered. The description adds real context beyond that: the whole-file SHA-256 for integrity verification and the pagination model via next_offset_chars. It does not disclose whether chunk boundaries can split lines or characters mid-codepoint, which matters for an agent stitching slices.

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 short sentences, both front-loaded: purpose and return shape first, then the usage condition and continuation path. No filler or restatement of the tool name.

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?

With an output schema present, return values need not be explained, and the annotations carry the safety profile. For a four-parameter read tool the description covers selection criteria and continuation adequately; only chunk-boundary semantics remain unstated.

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 path, max_chars, server_id and offset_chars are already documented; the baseline is 3. The description only reinforces the offset/pagination concept, and it references a field named 'next_offset_chars' that does not match the input parameter 'offset_chars', adding mild ambiguity rather than meaning.

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 names a specific verb and resource ('Read a bounded character slice of a text file') and states what is returned ('continuation metadata plus the whole-file SHA-256'). It distinguishes itself from a full-file read by scope ('bounded character slice', 'when full context is unnecessary'), though it never names the sibling read_file explicitly.

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?

'Use for large files when full context is unnecessary' gives a clear selection condition against a full-file read, and 'continue with next_offset_chars' explains the iterative workflow. There is no explicit exclusion naming read_file for small files, so the routing is inferable rather than stated.

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