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

With no annotations, the description carries the full burden and does well: it discloses that audio bytes are NOT retained, that only SHA-256 fingerprint and decoded image are anchored, that only Martin M1 (VIS 0x2C) is supported, unsupported modes return mode='unsupported' with detected hex, and unauthenticated calls are rejected. These are meaningful behavioral traits beyond the 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 multi-sentence but each sentence adds value: core action, privacy note, source requirements, supported format, and auth requirement. It is front-loaded with the primary verb and resource. Slightly longer than minimal but not wasteful.

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?

There is no output schema, so the description appropriately explains the return receipt bundle (Knox anchor, C2PA envelope, affidavit) and the unsupported-mode response (mode='unsupported' with hex). It also covers auth and input constraints. For a tool with nested objects and 5 parameters, it is fairly complete; missing details like error codes are minor.

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?

The input schema covers all parameters with descriptions (100% coverage), so the baseline is 3. The description adds general context about the workflow (e.g., audio not retained) but does not add per-parameter semantics beyond what the schema already provides. It neither compensates nor detracts.

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 begins with a precise action: 'Demodulate a presented slow-scan-television (SSTV) audio recording' and enumerates the output bundle (Knox anchor, C2PA envelope, affidavit). It clearly distinguishes from the sibling verify_sstv_decode by the verb 'decode' vs 'verify', making the tool's role unambiguous.

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?

It states that audio must be presented by the caller (WebSDR, customer-controlled capture, or owned audio) and that a Knox Bearer API key is required. It does not explicitly say 'use verify_sstv_decode for verification', but the context implies this tool is for decoding, which is sufficient for a competent agent. Missing explicit exclusions but not misleading.

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