summarise

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

Annotations cover only the safety profile (readOnly/openWorld/destructive), while the description discloses free/private/offline operation, concrete input ceilings (~30k words vs ~1000 dense log lines), the long-input split-and-combine behaviour with its latency and detail-loss cost, and the accuracy caveat ('can miss or distort details; check anything important'). This is unusually rich behavioral context beyond structured fields.

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?

Purpose is front-loaded in the first clause and every following sentence carries distinct information (cost, scope, limits, path hint, degradation, exclusions, caveat). It is dense and semicolon-heavy rather than cleanly chunked, which is the only thing keeping it below a 5.

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 no output schema, the description carries the return-shape burden and does so ('a paragraph, or at most 7 bullets'), matching the `length` enum. Input limits, degradation behaviour, the two input modes and the accuracy caveat are all present, so an agent has everything needed to call it correctly.

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, but the description adds genuine decision value: 'Pass `path` to a text file instead of `text` to avoid reading it yourself' explains the cost tradeoff between the two mutually exclusive inputs. It also reinforces the enum contract ('at most 7 bullets', 'a paragraph'), though it does not explain the `focus` parameter.

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 ('summarise') plus the resource and the execution substrate ('on-device model for Apple Foundation Models'), and immediately frames the output as a gist rather than a full record. An agent can distinguish this from classify/extract/ocr 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?

Explicit when-to-use ('condensing logs, documents, notes and transcripts into a gist') and explicit when-not ('Not for code, maths, reasoning or facts', 'not a full record'), plus a precondition ('filter bigger logs first (grep the errors)'). Nothing is left to inference.

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